Integer signedness error in the add_bytes_l2_c function in libavcodec/pngdsp.c in FFmpeg before 2.1 allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via crafted PNG data.
http://ffmpeg.org/security.html
http://git.libav.org/?p=libav.git;a=blob;f=Changelog;hb=refs/tags/v9.11
http://openwall.com/lists/oss-security/2013/11/26/7
http://openwall.com/lists/oss-security/2013/12/08/3
http://www.debian.org/security/2014/dsa-2855
https://github.com/FFmpeg/FFmpeg/commit/86736f59d6a527d8bc807d09b93f971c0fe0bb07