CVE-2026-88004High· 7.4▾ TwilightTraefik 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 a…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 40.7 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 13.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.3%
Last analysed / modified upstream
7 → 7.4
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.
traefik >= 3.2.0, < 3.7.13Upgrade past the affected range:
traefik 3.7.13Affected packages:
github.com/traefik/traefik/v3 >= 3.2.0, < 3.7.13Patched in:
github.com/traefik/traefik/v3 3.7.13Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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