CVE-2026-52845 Caddy: FastCGI header normalization bypass in `forward_auth copy_headers`

Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forwardauth copyheaders deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request later goes through phpfastcgi, Caddy normalizes HTTP headers int...

GO-2026-4639 Caddy forward_auth copy_headers allows Identity Injection and Privilege Escalation in github.com/caddyserver/caddy

Caddy forwardauth copyheaders Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation in github.com/caddyserver/caddy...

CVE-2026-30851

Caddy is an extensible server platform that uses TLS by default. From version 2.10.0 to before version 2.11.2, forwardauth copyheaders does not strip client-supplied headers, allowing identity injection and privilege escalation. This issue has been patched in version 2.11.2...

GHSA-7R4P-VJF4-GXV4 Caddy forward_auth copy_headers Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation

Summary Caddy's forwardauth directive with copyheaders generates conditional header-set operations that only fire when the upstream auth service includes the named header in its response. No delete or remove operation is generated for the original client-supplied request header with the same name...