CVE 2015-1803
The bdfReadCharacters function in bitmap/bdfread.c in X.Org libXfont before 1.4.9 and 1.5.x before 1.5.1 does not properly handle character bitmaps it cannot read, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and crash) and possibly execute arbitrary code via a crafted BDF font file.
See the 
CVE page on Mitre.org
for more details.
