Integer overflow in the ReadImage function in plug-ins/common/file-gif-load.c in the GIF image format plug-in in GIMP 2.8.x and earlier allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via crafted height and len properties in a GIF image file, which triggers a heap-based buffer overflow. NOTE: some of these details are obtained from third party information.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.