Cross-site request forgery (CSRF) vulnerability in ecrire/action/logout.php in SPIP before 2.1.24 allows remote attackers to hijack the authentication of arbitrary users for requests that logout the user via unspecified vectors.
https://www.debian.org/security/2013/dsa-2794
http://www.spip.net/fr_article5646.html
http://www.securitytracker.com/id/1029317