CVE-2026-20896 Gitea Docker Admin Impersonation via X-WEBAUTH-USER Header

Detects exploitation attempts against Gitea instances where an attacker impersonates an admin user by injecting the 'X-WEBAUTH-USER' header. This vulnerability typically occurs when 'REVERSE_PROXY_TRUSTED_PROXIES' is misconfigured to trust all proxies ('*'), allowing unauthenticated users to gain administrative access via header manipulation. The rule covers web request headers, container logs for suspicious admin creation, and process execution arguments associated with the exploitation.