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 (CVE-2016-6911).
Emmanuel Law discovered that the GD library incorrectly handled certain strings when creating images. If a user or automated system were tricked into processing a specially crafted image, an attacker could cause a denial of service, or possibly execute arbitrary code (CVE-2016-8670).