XScreenSaver: Privilege escalation

Background

XScreenSaver is a widely used screen saver collection shipped on systems running the X11 Window System.

Description

XScreenSaver incorrectly handles the results of the getpwuid() function in drivers/lock.c when using directory servers during a network outage.

Impact

A local user can crash XScreenSaver by preventing network connectivity if the system uses a remote directory service for credentials such as NIS or LDAP, which will unlock the screen.

Workaround

There is no known workaround at this time.

Resolution

All XScreenSaver users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=x11-misc/xscreensaver-5.02"