High 7.0Published Sep 10, 2026

CVE-2026-88004Traefik entrypoint header-name sanitization bypassed via request trailers

Updated under an hour ago (2026-10-19 06:25 UTC)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 7.0 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-436, CWE-807
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Sep 10, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

traefik traefik traefik:traefik (from the name)	from 3.2.0, < 3.7.13	CNA record
traefik traefik traefik:traefik	from 3.2.0 before 3.7.13	NVD

References

https://github.com/traefik/traefik/security/advisories/GHSA-v67p-phpq-fc8xx-refsource-confirm, patch, vendor-advisory
https://github.com/traefik/traefik/pull/13822x-refsource-misc, issue-tracking, patch
https://github.com/traefik/traefik/commit/55bbda4f65e0f9c533c870983a767a7081126db7x-refsource-misc, patch
https://github.com/traefik/traefik/releases/tag/v3.7.13x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.