Ubuntu: USN-3030-1 (CVE-2016-5116): GD library vulnerabilities

It was discovered that the GD library incorrectly handled memory when using
gdImageScaleTwoPass(). A remote attacker could possibly use this issue to
cause a denial of service. This issue only affected Ubuntu 14.04 LTS.
(CVE-2013-7456)

It was discovered that the GD library incorrectly handled certain malformed
XBM images. If a user or automated system were tricked into processing a
specially crafted XBM image, an attacker could cause a denial of service.
This issue only affected Ubuntu 14.04 LTS, Ubuntu 15.10 and Ubuntu 16.04
LTS. (CVE-2016-5116)

It was discovered that the GD library incorrectly handled memory when using
_gd2GetHeader(). A remote attacker could possibly use this issue to cause a
denial of service or possibly execute arbitrary code. (CVE-2016-5766)

It was discovered that the GD library incorrectly handled certain color
indexes. A remote attacker could possibly use this issue to cause a denial
of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 15.10 and
Ubuntu 16.04 LTS. (CVE-2016-6128)

It was discovered that the GD library incorrectly handled memory when
encoding a GIF image. A remote attacker could possibly use this issue to
cause a denial of service. (CVE-2016-6161)