Via OSS-sec:

>We found a read out-of-bound in the parsing of gif files using
>GraphicsMagick. This issue was tested in Ubuntu 14.04 (x86_64) using
>GraphicsMagick 1.3.18.
>
>$ ./gm identify overflow.gif
>
>AddressSanitizer: heap-buffer-overflow
>READ of size 1
>
>SUMMARY: AddressSanitizer: heap-buffer-overflow coders/gif.c:276 DecodeImage
>
>This issue is caused by the use of unintialized memory in DecodeImage and
>fortunately it was fixed here:
>
>http://marc.info/?l=graphicsmagick-commit&m=142283721604323&w=2
>
>Date:       2015-02-02 0:33:27
>
>coders/gif.c (DecodeImage): Assure that GIF decoder does not use
>unitialized data.
>
> +  (void) memset(prefix,0,MaxStackSize*sizeof(short));
> +  (void) memset(suffix,0,MaxStackSize);

Use CVE-2015-8808.

The scope of this CVE does not include the "FIXME: Is the logic for
this loop (or the loop which inits suffix and prefix arrays) correct?
Values are intentionally accessed outside of the explictly initialized
range of 'clear'." observation in the same commit.


References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-8808
http://seclists.org/oss-sec/2016/q1/290