A vulnerability has been discovered and corrected in libxfont:

The LZW decompressor in (1) the BufCompressedFill function in
fontfile/decompress.c in X.Org libXfont before 1.4.4 and (2)
compress/compress.c in 4.3BSD, as used in zopen.c in OpenBSD before
3.8, FreeBSD, NetBSD, FreeType 2.1.9, and other products, does not
properly handle code words that are absent from the decompression
table when encountered, which allows context-dependent 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-2011-2896 (CVE-2011-2895).

The updated packages have been patched to correct this issue.