There is an integer overflow in PHP versions 5.2.1 and below in ext/gd/libgd/wbmp.c in the function readwbmp.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/55791/php521-overflow.txt
Source: https://packetstormsecurity.com/files/55791/php521-overflow.txt.html