Debian Security Advisory 1376-1 – iKees Huijgen discovered that under certain circumstances KDM, an X session manage for KDE, it is possible for KDM to be tricked into allowing user logins without a password.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/59526/dsa-1376-1.txt
Source: https://packetstormsecurity.com/files/59526/Debian-Linux-Security-Advisory-1376-1.html