Several security issues were fixed in GD.
It was discovered that GD incorrectly handled memory when processing certain images. A remote attacker could use this issue with a specially crafted image file to cause GD to crash, resulting in a denial of service, or possibly execute arbitrary code.
28 February 2019
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in GD.
It was discovered that GD incorrectly handled memory when processing certain images. A remote attacker could use this issue with a specially crafted image file to cause GD to crash, resulting in a denial of service, or possibly execute arbitrary code.
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.