Ubuntu Security Notice 3117-1 – Ibrahim El-Sayed discovered that the GD library incorrectly handled certain malformed Tiff images. If a user or automated system were tricked into processing a specially crafted Tiff image, an attacker could cause a denial of service. Ke Liu discovered that the GD library incorrectly handled certain integers when processing WebP images. If a user or automated system were tricked into processing a specially crafted WebP image, an attacker could cause a denial of service, or possibly execute arbitrary code. This issue only applied to Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. Various other issues were also addressed.