Ubuntu Security Notice 383-1 – Tavis Ormandy discovered that libpng did not correctly calculate the size of sPLT structures when reading an image. By tricking a user or an automated system into processing a specially crafted PNG file, an attacker could exploit this weakness to crash the application using the library.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/52296/USN-383-1.txt
Source: https://packetstormsecurity.com/files/52296/Ubuntu-Security-Notice-383-1.html