VulnerabilityPublished 26 Oct 2026

CVE-2026-113714: virtualenv · Downloaded wheel selection and caching precede verification

Affects hatchSource GCVE Database

Authoritative record:CVE-2026-113714· Low 2.3

Not known to be exploited · CVSS 2.3 Low : upgrade to 1.18.1_2 when convenient.

Data as of 27 Oct 2026, 06:43 UTC

CVSS 4.0 base score

2.3Low

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 1.18.1_2

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: High
Attack Requirements: Present
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques, for example, circumvention of address space randomization (ASLR) or data execution prevention (DEP) must be performed for the attack to be successful; Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Attack Requirements: Present: The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade hatch to 1.18.1_2.

Affected software

Product	Affected	Fixed in
Homebrewhatch`pkg:brew/hatch`Other threats	Affected >=1.18.1_1 <1.18.1_2	Fixed in 1.18.1_2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

## Summary Wheel downloads go directly into the reusable wheelhouse, while the verification target is selected from pip's textual output. A verification failure does not remove the downloaded file from that cache. Anthropic's OSS Scanner reported this as `ANT-2026-ST00DRO3` in `virtualenv-20261015-005`, received on 15 October 2026. ## Affected area Download selection and promotion into the reusable wheel cache. ## Attacker-controlled input A download must fail verification, or the archive selected from pip output must differ from the file later reused. Default-index digest verification must be enabled. Existing custom-index exceptions are outside the promised PyPI comparison. ## Affected code The relevant 21.14.8 source is in [wheel download and digest check](https://github.com/pypa/virtualenv/blob/a795ab116356afde11039cf2763d77e8a06da738/src/virtualenv/seed/wheels/acquire.py). ## Mechanism `download_wheel()` tells pip to write directly into the reusable `wheel/house` cache. It then selects a path to hash from the first `Saved ` line in pip's stdout, rather than from the file pip actually placed there. A package index can inject such a line through a discarded link's `data-requires-python` attribute. A separate failure exists without the forged line: a digest mismatch raises after the downloaded wheel has entered the cache, and the rejected bytes remain there. Later wheel selection does not hash the cached file again. ## Reproduction and evidence The scanner used a local index configured in `pip.conf`, with PyPI digest comparison still enabled. In the control case it served a modified pip wheel alone. `virtualenv --upgrade-embed-wheels` refused the mismatch, and a subsequent environment used the bundled pip. In the attack case the index added a link whose `data-requires-python` contained a forged `Saved <path>` line pointing at a genuine bundled wheel. The upgrade then exited without a digest error, recorded the modified wheel in its update log, and a later environment's `pip --version` ran a line added by the index. The reproduction used a known absolute path to the genuine bundled wheel; that prerequisite is part of this variant. The report also shows that a refused wheel can replace a previously accepted file of the same name in `wheel/house`, leaving rejected bytes available for later use. It does not claim to bypass TLS or affect the default PyPI setup. The gap follows the digest check added in #3251, first released in 21.7.12. [PR #3430](https://github.com/pypa/virtualenv/pull/3430) downloads to a private temporary directory, verifies the actual archive, and promotes it only after acceptance. ## Attack sequence ```mermaid sequenceDiagram participant I as Configured index participant P as pip download participant C as wheel/house cache participant V as virtualenv digest check participant N as New environment I->>P: modified wheel and forged Saved line P->>C: write modified wheel directly P-->>V: stdout names genuine bundled wheel V->>V: hash genuine wheel and accept V->>C: record modified wheel for reuse C->>N: seed modified pip without rehash Note over P,C: Even a rejected wheel can remain in the cache ``` ## Reproducer files The following files are from the scanner report for `ANT-2026-ST00DRO3`. They were tested against commit `a857a7823c73` in the scanner image. The `repro` entrypoint expects companion files under `/tmp/repro.d`; cases that change user IDs need a disposable root-capable container. The last output line is `BUG` when the reported behavior occurs. These files are included as evidence and were not rerun for this advisory update. **`repro`** ```text #!/usr/bin/env python3 import atexit import hashlib import json import os import shutil import subprocess import sys from pathlib import Path companions = Path("/tmp/repro.d") work = Path("/tmp/forged-saved-line") home = work / "home" app_data = home / ".cache" / "virtualenv" this_python = f"{sys.version_info.major}.{sys.version_info.minor}" # the target; each Python has its own update log update_log_of_pip = app_data / "wheel" / this_python / "embed" / "3" / "pip.json" virtualenv = [sys.executable, companions / "virtualenv_with_local_pypi_json.py", work / "pypi"] as_user = {"cwd": home, "env": {"HOME": str(home), "PATH": os.environ["PATH"]}, "capture_output": True, "text": True} added_code_prints = "code added by the index" # the line index_serves_modified_pip.py adds to pip/__init__.py def user_upgrades_seed_wheels_and_creates_env(): # each case starts from an empty app-data shutil.rmtree(app_data, ignore_errors=True) shutil.rmtree(home / "env", ignore_errors=True) upgrade = subprocess.run([*virtualenv, "--upgrade-embed-wheels"], **as_user) # --no-periodic-update: the background update is another process, which the PyPI stand-in does not reach subprocess.run([*virtualenv, "--no-periodic-update", "env"], **as_user, check=True) pip_version = s

References

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