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Not in CISA KEV

CVE-2026-65600 — v2

CVE-2026-65600 is a Path Traversal vulnerability in github.com/traefik/traefik/v2. A fix is available for github.com/traefik/traefik/v2 — see the affected versions and patch details below.

Traefik before v2.11.52 Authentication Bypass via ReplacePathRegex

Also known asGHSA-cxjq-mrr5-89rvGO-2026-6208
Published
Jul 22, 2026
Updated
Sep 9, 2026
Affected
4 pkgs
Patched
3 / 4
Exploits
None indexed
Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-65600.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs35th percentile — riskier than 35% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

4 pkgs affected
🐹github.com/traefik/traefik/v2🐹github.com/traefik/traefik/v3🐹github.com/traefik/traefik/v3🐹github.com/traefik/traefik

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex "^/api(.*)", replacement "/$1"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a backend that normalizes paths resolves to a protected route, bypassing authentication middleware. Fixed in v2.11.52, v3.6.23, and v3.7.7.

Affected Packages

4 total 3 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/traefik/traefik/v2all versions2.11.52go get github.com/traefik/traefik/v2@v2.11.52
🐹Gogithub.com/traefik/traefik/v3all versions3.6.23go get github.com/traefik/traefik/v3@v3.6.23
🐹Gogithub.com/traefik/traefik/v3≥ 3.7.0&&< 3.7.73.7.7go get github.com/traefik/traefik/v3@v3.7.7
🐹Gogithub.com/traefik/traefikall versionsNo fix

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/traefik/traefik/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update github.com/traefik/traefik/v2 to 2.11.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-65600 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-65600 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-65600. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatCritical

This Critical flaw in Traefik's `ReplacePathRegex` middleware allows an unauthenticated remote attacker to bypass authentication. When the middleware is configured with a regex that captures user-controlled path segments without a mandatory path separator, it can forward un-normalized paths. This enables access to…

ProductFixed inAdvisory
Red Hat OpenShift Dev Spaces 3.30devspaces/traefik-rhel9:1787756799RHSA-2026:62260

Frequently Asked Questions

Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex "^/api(.*)", replacement "/$1"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a b
O3 Security · Impact-Aware SCA

Is CVE-2026-65600 in your dependencies?

O3 Security finds CVE-2026-65600 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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CVE-2026-65600: v2 Path Traversal | O3 Security