Ubuntu Security Notice USN-210-1 – A buffer overflow was found in the “pnmtopng” conversion program. By tricking an user (or automated system) to process a specially crafted PNM image with pnmtopng, this could be exploited to execute arbitrary code with the privileges of the user running pnmtopng.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/40779/usn-210-1.txt
Source: https://packetstormsecurity.com/files/40779/usn-210-1.txt.html

