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CVE-2026-88008

Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization PUBLISHED

Description (CNA)

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching Protocols, Traefik enters a raw tunnel and no longer applies routers, BasicAuth, ForwardAuth, IPAllowList, RateLimit, access logging, metrics, or tracing to later HTTP/2 requests, allowing an unauthenticated request through an unprotected route to reach protected paths on the same backend. This issue is fixed in 2.11.57 and 3.7.13.

Affected (CNA)

Vendor / productVersions
traefik / traefikaffected >= 2.11.26, < 2.11.57; affected >= 3.4.2, < 3.7.13

CWE

CWE-444, CWE-863

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.