Ubuntu Security Notice 472-1 – It was discovered that libpng did not correctly handle corrupted CRC in grayscale PNG images. By tricking a user into opening a specially crafted PNG, a remote attacker could cause the application using libpng to crash, resulting in a denial of service.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/57151/USN-472-1.txt
Source: https://packetstormsecurity.com/files/57151/Ubuntu-Security-Notice-472-1.html