SPIP before version 4.4.18 contains a missing authorization vulnerability in sensitive actions under ecrire/action/ that allows unauthenticated attackers to invoke privileged actions by supplying only a valid CSRF nonce without any server-side permission check. Attackers can bypass template-level authorization guards through direct HTTP requests to invoke actions such as editer_auteur, enabling arbitrary account password rewrites including administrator accounts and resulting in full account takeover.

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.

Affected: Ubuntu:Pro:16.04:LTS: spip, Ubuntu:Pro:18.04:LTS: spip, Ubuntu:Pro:20.04:LTS: spip, Ubuntu:22.04:LTS: spip, Ubuntu:24.04:LTS: spip, Ubuntu:26.04:LTS: spip

SPIP before version 4.4.18 contains a missing authorization vulnerability in sensitive actions under ecrire/action/ that allows unauthenticated attackers to invoke privileged actions by supplying only a valid CSRF nonce without any server-side permission check. Attackers can bypass template-level authorization guards through direct HTTP requests to invoke actions such as editer_auteur, enabling arbitrary account password rewrites including administrator accounts and resulting in full account takeover.