1sealsemantic last-mile verification

Research / Finding

Case-Sensitive Bypass in Connection Header Allows Removal of X-Forwarded Headers

F-TRAEFIK-003

Public snapshot: 26 Sep 2026. Status, releases and attribution belong to each source below; none is inferred from another record.

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Recorded evidence

7.5high
CVE-2026-29054CVEtraefik/traefik

Case-Sensitive Bypass in Connection Header Allows Removal of X-Forwarded Headers

Upstream fixed versions: Traefik: v2.11.38; Traefik: v3.6.9

patched
details
Finding IDs
F-TRAEFIK-003
CVE
CVE-2026-29054
GHSA
GHSA-92mv-8f8w-wq52
Status
patched
Fixed in
Traefik: v2.11.38; Traefik: v3.6.9
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVE registry state
PUBLISHED
CVE state checked
Upstream title
Case-Sensitive Bypass in Connection Header Allows Removal of X-Forwarded Headers
Upstream CWE
CWE-178
Upstream publication
Upstream updated
Metadata fetched
Upstream fixed versions
Traefik: v2.11.38; Traefik: v3.6.9
Upstream affected ranges
Traefik: >= v2.11.9, <= v2.11.37; Traefik: >= v3.1.3, <= v3.6.8
Upstream @1seal credit
@1seal: reporter (accepted)

F-TRAEFIK-003: Input / state handling. Case handling leaves hop-by-hop headers inconsistently processed. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-TRAEFIK-003

Security area (1seal assessment): Semantics. Case-dependent Connection header processing gives inconsistent meaning to forwarded-header removal, a request-interpretation boundary. Reviewed 24 Sep 2026.

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