SquirrelMail, a webmail application, does not employ a user-specific token for webforms. This allows a remote attacker to perform a Cross Site Request Forgery attack. The attacker may hijack the authentication of unspecified victims and send messages or change user preferences among other actions, by tricking the victim into following a link controled by the offender. In addition, a denial-of-service was fixed, which could be triggered when a passwords containing 8-bit characters was used to log in . For the stable distribution , these problems have been fixed in version 1.4.15-4+lenny3.1. For the testing distribution and the unstable distribution , these problems have been fixed in version 1.4.21-1. We recommend that you upgrade your squirrelmail packages.