Heap-based buffer overflow in util/gif2rgb.c in gif2rgb in giflib 5.1.2 allows remote attackers to cause a denial of service (application crash) via the background color index in a GIF file.
Heap-based buffer overflow in giffix.c in giffix in giflib 5.1.1 allows attackers to cause a denial of service (program crash) via crafted image and logical screen width fields in a GIF file.