USN-474-1: xscreensaver vulnerability

Ubuntu Security Notice USN-474-1

12th June, 2007

xscreensaver vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 7.04
  • Ubuntu 6.10
  • Ubuntu 6.06 LTS


It was discovered that xscreensaver did not correctly validate the
return values from network authentication systems such as LDAP or NIS.
A local attacker could bypass a locked screen if they were able to
interrupt network connectivity.

Update instructions

The problem can be corrected by updating your system to the following package version:

Ubuntu 7.04:
xscreensaver 4.24-5ubuntu2.1
Ubuntu 6.10:
xscreensaver 4.24-4ubuntu2.1
Ubuntu 6.06 LTS:
xscreensaver 4.23-4ubuntu8.1

To update your system, please follow these instructions:

After a standard system upgrade you need to restart your session to
effect the necessary changes.