Xvid is a popular open source video codec licensed under the GPL.
Trixter Jack discovered an array indexing error in the get_intra_block() function in the file src/bitstream/mbcoding.c. The get_inter_block_h263() and get_inter_block_mpeg() functions in the same file were also reported as vulnerable.
An attacker could exploit these vulnerabilities to execute arbitrary code by tricking a user or automated system into processing a malicious video file with an application that makes use of the Xvid library.
There is no known workaround at this time.
All Xvid users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=media-libs/xvid-1.1.3"