SPIP before 4.4.18 contains a missing authorization vulnerability in the administrative action endpoints under ecrire/action/ that allows unauthenticated attackers to perform privileged actions by supplying a valid HMAC-SHA256 nonce without any server-side permission check via autoriser(). Attackers can obtain a valid nonce, compute it for any action as the anonymous user, and invoke the editer_auteur action directly over HTTP to reset the password of any user account, including the administrator.
Analyzing vulnerability vectors…