It was discovered that libpng did not properly initialize memory when decoding certain 1-bit interlaced images. If a user or automated system were tricked into processing crafted PNG images, an attacker could possibly use this flaw to read sensitive information stored in memory. This issue only affected Ubuntu 6.06 LTS, 8.04 LTS, 8.10 and 9.04. It was discovered that libpng did not properly handle certain excessively compressed PNG images. If a user or automated system were tricked into processing a crafted PNG image, an attacker could possibly use this flaw to consume all available resources, resulting in a denial of service