Ubuntu Security Notice 298-1 – Xavier Roche discovered that libgd’s function for reading GIF image data did not sufficiently verify its validity. Specially crafted GIF images could cause an infinite loop which used up all available CPU resources. Since libgd is often used in PHP and Perl web applications, this could lead to a remote Denial of Service vulnerability.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/47533/USN-298-1.txt
Source: https://packetstormsecurity.com/files/47533/Ubuntu-Security-Notice-298-1.html