The svq1_decode_frame function in the SVQ1 decoder (svq1dec.c) in libavcodec in FFmpeg 0.5.x before 0.5.7, 0.6.x before 0.6.4, 0.7.x before 0.7.9, and 0.8.x before 0.8.8; and in Libav 0.5.x before 0.5.6, 0.6.x before 0.6.4, and 0.7.x before 0.7.3 allows remote attackers to cause a denial of service (memory corruption) via a crafted SVQ1 stream, related to "dimensions changed."
http://www.securityfocus.com/archive/1/520620
http://www.mandriva.com/security/advisories?name=MDVSA-2012:076
http://www.mandriva.com/security/advisories?name=MDVSA-2012:075
http://www.mandriva.com/security/advisories?name=MDVSA-2012:074
http://ubuntu.com/usn/usn-1333-1
http://ubuntu.com/usn/usn-1320-1
http://git.videolan.org/?p=ffmpeg.git%3Ba=commit%3Bh=6e24b9488e67849a28e64a8056e05f83cf439229
http://git.libav.org/?p=libav.git%3Ba=commit%3Bh=6e24b9488e67849a28e64a8056e05f83cf439229