ADVISORYHIGH6d ago · Sep 10, 2026
Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization

There is a high-severity request-smuggling vulnerability in Traefik's handling of the HTTP/1.1 Upgrade mechanism. Since Traefik moved to unencrypted HTTP/2 with prior knowledge (Go 1.24), a client-initiated Upgrade: h2c request header and its…
Read it at github.com/traefik/traefik/v3