VulnerabilityPublished 1 Aug 2026Updated 6 Aug 2026

CVE-2026-67309: Traefik · Kubernetes Ingress NGINX RewriteTarget Path Traversal Allows Route-Level Authentication Bypass

Affects github.com/traefik/traefik/v3Source GCVE Database

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Not known to be exploited · CVSS 7.8 High · fixed in 3.7.8 : patch github.com/traefik/traefik/v3 soon.

Data as of 1 Nov 2026, 11:03 UTC

CVSS 4.0 base score

7.8High

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.7.8

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: High
Subsequent system integrity: High
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: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
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: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Subsequent system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the Subsequent System. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the Subsequent 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 1 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 1 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Affected software

Product	Affected	Fixed in
GitHubtraefik/traefik`pkg:github/traefik/traefik`Other threats	Affected >=3.7.0 <=3.7.7	Fixed in–

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AI-suggested

Upgrade Traefik to version 3.7.8 or later, where this path traversal vulnerability in the Kubernetes Ingress NGINX provider's RewriteTarget middleware is fixed. No other mitigations are specified or required once the patch is applied.

Description

## Summary There is a high severity vulnerability in Traefik's Kubernetes Ingress NGINX provider. When an Ingress uses the `nginx.ingress.kubernetes.io/rewrite-target` annotation with a regular expression that captures attacker-controlled text without requiring a path separator (for example path `/api(.*)` with rewrite target `/$1`), the generated `RewriteTarget` middleware can turn an initially safe request path into a dot-segment traversal path after the router has already been selected. ## Patches - https://github.com/traefik/traefik/releases/tag/v3.7.8 ## 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 Ingress NGINX provider creates an internal `RewriteTarget` middleware for the `nginx.ingress.kubernetes.io/rewrite-target` annotation. When an Ingress path captures attacker-controlled text without requiring a path separator, the middleware can turn an initially safe path into a dot-segment traversal path after Traefik has already selected the router. For example, with Ingress path `/api(.*)` and rewrite target `/$1`, an unauthenticated request to `/api../admin` follows this flow: 1. The default entry-point path sanitizer leaves `/api../admin` unchanged because `api..` is one ordinary segment. 2. The public router's `PathRegexp("(?i)^/api(.*)")` rule matches. 3. `RewriteTarget` captures `../admin` and creates `/../admin`. 4. The middleware forwards `/../admin` without checking whether path normalization changes it. 5. A backend that normalizes paths resolves `/../admin` to `/admin`. 6. The request reaches content intended to be reachable only through a separate `/admin` router with BasicAuth, DigestAuth, or ForwardAuth. This is an unpatched sibling of [GHSA-cxjq-mrr5-89rv](https://github.com/traefik/traefik/security/advisories/GHSA-cxjq-mrr5-89rv), which added post-replacement normalization validation to `ReplacePathRegex`. The separate ingress-nginx `RewriteTarget` implementation did not receive the same validation. The bypass remains exploitable in the patched Traefik v3.7.7 release. ## Severity **Proposed severity:** Critical **CVSS 3.1:** 9.1 — `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N` - Attack vector: Network - Attack complexity: Low once the affected routing pattern exists - Privileges required: None - User interaction: None - Scope: Unchanged - Confidentiality: High - Integrity: High - Availability: None **Primary weakness:** CWE-22 — Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) **Secondary weakness:** CWE-288 — Authentication Bypass Using an Alternate Path or Channel The practical impact depends on the protected backend paths. If they are read-only or low sensitivity, environmental severity may be lower. ### Exploitation Preconditions - The Kubernetes Ingress NGINX provider is enabled. - A public Ingress uses `rewrite-target` with a regex that can capture `..` adjacent to the matched prefix, such as `/api(.*)` with `/$1`. - A protected router exposes another path on the same backend, such as `/admin`, and relies on a Traefik authentication or authorization middleware. - The backend normalizes dot segments before dispatching the request. These are deployment prerequisites; the remote attacker needs no credentials or special timing. ## Affected Components ### Confirmed versions - Traefik v3.7.0 through v3.7.7 - Current `master` at commit `b93f02cd07b79490fb8c8f02e301a7a1ec553195` - Current `v3.7` branch at `69259c3acc9d4bdc065cb2e3b83336f7de3e7038` The vulnerable middleware is present in every stable v3.7 release checked. The v2.11 and v3.6 branches do not contain this ingress-nginx `RewriteTarget` implementation. ### Code locations - `pkg/provider/kubernetes/ingress-nginx/middleware.go:257-274` - Converts the Ingress path and `rewrite-target` annotation directly into `dynamic.RewriteTarget` configuration. - `pkg/middlewares/ingressnginx/rewritetarget/rewrite_target.go:85-157` - Performs capture-based path rewriting and forwards the rewritten path without normalization validation. - `pkg/server/middleware/middlewares.go:346-353` - Instantiates the vulnerable middleware in the live HTTP chain. ## Root Cause The provider passes the route regex and annotation replacement into the middleware: ```go loc.RewriteTarget = &dynamic.RewriteTarget{ Regex: loc.Path, Replacement: rewrite, } ``` `RewriteTarget.ServeHTTP` then derives a path from attacker-controlled capture groups: ```go newTarget = rt.regexp.ReplaceAllString(currentPath, rt.replacement) req.URL.RawPath = newTarget req.URL.Path, err = url.PathUnescape(req.URL.RawPath) req.RequestURI = req.URL.RequestURI() rt.next.ServeHTTP(rw, req) ``` There is no invariant check between `PathUnescape` and forwarding to ensure that `req.URL.Path` equals its normalized form. Because routing happen

Impact

An attacker can bypass route-level authentication mechanisms (BasicAuth, DigestAuth, ForwardAuth) by exploiting the path traversal vulnerability, gaining unauthorized access to protected backend endpoints. This undermines the security controls intended to restrict access to sensitive routes, potentially exposing administrative or otherwise protected functionality.

Summary

Traefik versions >=3.7.0 and <=3.7.7 have a path traversal vulnerability in the Kubernetes Ingress NGINX provider's RewriteTarget middleware, triggered by regex path captures that do not require a path separator. An attacker can craft requests such as /api../admin that are rewritten to '/../admin' and forwarded without proper normalization validation. If the backend normalizes dot segments, this can lead to access to protected endpoints that should be secured by separate authentication mechanisms, effectively bypassing route-level authentication controls. The vulnerability is tracked as CVE-2026-67309 and is resolved in Traefik version 3.7.8.

CWE-22Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #6OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Path Traversal (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
Using Escaped Slashes in Alternate Encoding (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-288Authentication Bypass Using an Alternate Path or Channel (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
Architecture and Design
Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.2.3 (opens in a new tab)
V1.2.2 (opens in a new tab)
V1.2.4 (opens in a new tab)
Attack patterns
Directory Indexing (opens in a new tab)
Exploitation of Thunderbolt Protection Flaws (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 1 Aug 2026, 22:32 UTC

WeaknessesCWE-22, CWE-288

Technical details

References

Community reviews

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