CVE 2011-4579
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."
See the 
CVE page on Mitre.org
for more details.
