Heap-based buffer overflow in the encodeslice function in libavcodec/proresenckostya.c in FFMpeg before 1.1.14, 1.2.x before 1.2.8, 2.x before 2.2.7, and 2.3.x before 2.3.3 and Libav before 10.5 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via unspecified vectors.

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."