Traefik affected by Go HTTP Request Smuggling Vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary net/http: request smuggling through invalid chunked data: The net/http package accepts data in the chunked transfer encoding containing an invalid chunk-size line terminated by a bare LF. When used in conjunction with a server or proxy which incorrectly interprets a bare LF in a chunk extension as part of the extension, this could permit request smuggling. [CVE-2025-22871] Vendor Affected Components: Go: 1.23.x < 1.23.8 More Details: CVE-2025-22871 Patches - https://github.com/traefik/traefik/releases/tag/v2.11.24 - https://github.com/traefik/traefik/releases/tag/v3.3.6 - https://github.com/traefik/traefik/releases/tag/v3.4.0-rc2

Published by the source

18 Apr 2025, 19:35 UTC

Last modified by the source

18 Apr 2025, 19:35 UTC

Source last checked

26 Oct 2026, 15:09 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5423-jcjm-2gpv

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# Patch Next advisory brief: GHSA-5423-jcjm-2gpv

Advisory: Traefik affected by Go HTTP Request Smuggling Vulnerability
IDs: GHSA-5423-jcjm-2gpv
Record: https://patchnext.com/advisories/ghsa-5423-jcjm-2gpv (revision 1, source checked 26 Oct 2026, 15:09 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/traefik/traefik/v3 3.4.0-rc2, 3.3.6; github.com/traefik/traefik/v2 2.11.24. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/traefik/traefik/v3: affected < 3.3.6; >= 3.4.0-rc1, <= 3.4.0-rc1; fixed in 3.3.6, 3.4.0-rc2
- Go github.com/traefik/traefik/v2: affected < 2.11.24; fixed in 2.11.24

## Suggested inspection (read-only)
- Go github.com/traefik/traefik/v3: check the installed version with your package manager.
- Go github.com/traefik/traefik/v2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/traefik/traefik/v3, github.com/traefik/traefik/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-5423-jcjm-2gpv (GitHub-reviewed advisory GHSA-5423-jcjm-2gpv lists affected ranges: Go github.com/traefik/traefik/v2 >=0 =0 =3.4.0-rc1 <=3.4.0-rc1)

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