A vulnerability has been discovered and corrected in gimp:

The LZW decompressor in the LWZReadByte function in giftoppm.c in
the David Koblas GIF decoder in PBMPLUS, as used in the gif_read_lzw
function in filter/image-gif.c in CUPS before 1.4.7, the LZWReadByte
function in plug-ins/common/file-gif-load.c in GIMP 2.6.11 and earlier,
the LZWReadByte function in img/gifread.c in XPCE in SWI-Prolog 5.10.4
and earlier, and other products, does not properly handle code words
that are absent from the decompression table when encountered, which
allows remote attackers to trigger an infinite loop or a heap-based
buffer overflow, and possibly execute arbitrary code, via a crafted
compressed stream, a related issue to CVE-2006-1168 and CVE-2011-2895
(CVE-2011-2896).

The updated packages have been patched to correct these issues.