scan.c for LibXPM may allow attackers to execute arbitrary code via a negative bitmapunit value that leads to a buffer overflow.
Integer overflow in the bdfReadCharacters function in bdfread.c in (1) X.Org libXfont before 20070403 and (2) freetype 2.3.2 and earlier allows remote authenticated users to execute arbitrary code via crafted BDF fonts, which result in a heap overflow.