The sws_init_context function in libswscale/utils.c in FFmpeg before 2.7.2 does not initialize certain pixbuf data structures, which allows remote attackers to cause a denial of service (segmentation violation) or possibly have unspecified other impact via crafted video data. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-6824