Traefik is an open source HTTP reverse proxy and load balancer. From 3.2.0 until 3.7.13, Traefik entrypoint defenses aliasHeadersStrategy, underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but not req.Trailer, allowing an unauthenticated client to submit an aliasing or trusted header name in an HTTP/1.1 chunked trailer or an HTTP/2 trailer. When the retry or buffering middleware reads the body before the reverse proxy clones the request, the attacker-controlled trailer value reaches a backend that merges trailers into the header namespace, bypassing the documented delete or reject behavior and potentially spoofing identity or forwarded routing data. This issue is fixed in 3.7.13.

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact High

Subsequent System Integrity Impact High

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
traefik traefik affected
Version Status Constraints
>= 3.2.0, < 3.7.13 affected —

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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/traefik/traefik/commit/55bbda4f65e0f9c533c870983a767a7081126db7 cve-icon cve-icon
https://github.com/traefik/traefik/pull/13822 cve-icon cve-icon
https://github.com/traefik/traefik/releases/tag/v3.7.13 cve-icon cve-icon
https://github.com/traefik/traefik/security/advisories/GHSA-v67p-phpq-fc8x cve-icon cve-icon
History

Thu, 10 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 10 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
Description Traefik is an open source HTTP reverse proxy and load balancer. From 3.2.0 until 3.7.13, Traefik entrypoint defenses aliasHeadersStrategy, underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but not req.Trailer, allowing an unauthenticated client to submit an aliasing or trusted header name in an HTTP/1.1 chunked trailer or an HTTP/2 trailer. When the retry or buffering middleware reads the body before the reverse proxy clones the request, the attacker-controlled trailer value reaches a backend that merges trailers into the header namespace, bypassing the documented delete or reject behavior and potentially spoofing identity or forwarded routing data. This issue is fixed in 3.7.13.
Title Traefik entrypoint header-name sanitization bypassed via request trailers
Weaknesses CWE-436
CWE-807
References
Metrics cvssV4_0

{'score': 7, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-10T15:10:44.794Z

Reserved: 2026-09-09T19:19:27.406Z

Link: CVE-2026-88004

cve-icon Vulnrichment

Updated: 2026-09-10T15:10:41.900Z

cve-icon NVD

Status : Received

Published: 2026-09-10T15:17:54.940

Modified: 2026-09-10T16:18:07.560

Link: CVE-2026-88004

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-10T16:00:14Z

Weaknesses