Fabio - Incomplete fix for CVE-2025-48865: operator-configured trust headers (clientip/tls/requestid) still strippable via the Connection header

Overview

Fabio is an HTTP(S) and TCP router for deploying applications managed by consul. From 1.6.6 until 1.7.2, the CVE-2025-48865 fix in proxy/http_headers.go uses protectHeaders for a hardcoded set of forwarded headers but omits the operator-configured ClientIPHeader, TLSHeader, and RequestID names. In proxy/http_proxy.go, HTTPProxy.ServeHTTP calls addHeaders to set these trust headers before Go ReverseProxy processes the inbound Connection header, allowing an unauthenticated client to name and remove the configured headers before the request reaches the backend. Deployments that enable the corresponding proxy.header options can therefore lose client-IP, TLS-termination, or request-correlation signals used by backend authorization and auditing; the options are empty by default, and the hardcoded protected forwarded headers are unaffected. This issue is fixed in version 1.7.2.

Affected

• fabio >= 1.6.6, < 1.7.2

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.