KDM is the desktop manager included with the K Desktop Environment.
Firstly, versions of KDM <=3.1.3 are vulnerable to a privilege escalation bug with a specific configuration of PAM modules. Users who do not use PAM with KDM and users who use PAM with regular Unix crypt/MD5 based authentication methods are not affected.
Secondly, KDM uses a weak cookie generation algorithm. Users are advised to upgrade to KDE 3.1.4, which uses /dev/urandom as a non-predictable source of entropy to improve security.
A remote or local attacker could gain root privileges.
There is no known workaround at this time.
It is recommended that all Gentoo Linux users who are running kde-base/kdebase <=3.1.3 upgrade:
# emerge sync
# emerge -pv '>=kde-base/kde-3.1.4'
# emerge '>=kde-base/kde-3.1.4'
# emerge clean