The problem can be corrected by upgrading the affected package to version 1-rc5-1ubuntu2.2 (for Ubuntu 4.10) and 1.0-1ubuntu3.1 (for Ubuntu 5.04). In general, a standard system upgrade is sufficient to effect the necessary changes.
Details follow:
Two buffer overflows have been discovered in the MMS and Real RTSP stream handlers of the Xine library. By tricking a user to connect to a malicious MMS or RTSP video/audio stream source with an application that uses this library, an attacker could crash the client and possibly even execute arbitrary code with the privileges of the player application.