The problem can be corrected by upgrading the affected package to
version 4.1.0b1-6ubuntu0.1 (for Ubuntu 4.10), 4.1.3-1ubuntu0.1 (for
Ubuntu 5.04), or 4.1.3-2ubuntu0.1 (for Ubuntu 5.10). In general, a
standard system upgrade is sufficient to effect the necessary changes.
Chris Evans discovered several buffer overflows in the libungif
library. By tricking an user (or automated system) into processing a
specially crafted GIF image, this could be exploited to execute
arbitrary code with the privileges of the application using libungif.