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CVE 2011-3937

The H.263 codec (libavcodec/h263dec.c) in FFmpeg 0.7.x before 0.7.12, 0.8.x before 0.8.11, and unspecified versions before 0.10, and in Libav 0.5.x before 0.5.9, 0.6.x before 0.6.6, 0.7.x before 0.7.5, and 0.8.x before 0.8.1 has unspecified impact and attack vectors related to "width/height changing with frame threads."

See the CVE page on Mitre.org for more details.