The GD library could be made to crash or run programs if it processed a specially crafted image file.
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)
11 July 2016
A security issue affects these releases of Ubuntu and its derivatives:
The GD library could be made to crash or run programs if it processed a specially crafted image file.
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)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system update will make all the necessary changes.