CVE-2026-56654: Gitea: Privilege Escalation via Access Token Scope Escalation in API

Gitea’s API endpoint for creating Personal Access Tokens (POST /users/{username}/tokens) is protected by a middleware (reqBasicOrRevProxyAuth) that is intended to require password-based authentication, preventing a compromised token from being used to mint new ones. However, when a token is passed in the Authorization: Basic <token>:x-oauth-basic format, the Basic auth handler validates it and sets AuthedMethod="basic", causing IsBasicAuth=true and fooling the middleware into passing the request. Once past the guard, the token creation handler applies no scope ceiling — it will create a new token with any requested scope regardless of the caller’s scope. An attacker with a restricted token (e.g. write:user from a leaked CI secret) can therefore create a fully-privileged all-scoped token without knowing the account password.