LibTIFF could be made to crash or run programs as your login if it opened a specially crafted file.
It was discovered that LibTIFF incorrectly handled certain malformed images. If a user or automated system were tricked into opening a specially crafted image, a remote attacker could crash the application, leading to a denial of service, or possibly execute arbitrary code with user privileges.
26 March 2018
A security issue affects these releases of Ubuntu and its derivatives:
LibTIFF could be made to crash or run programs as your login if it opened a specially crafted file.
It was discovered that LibTIFF incorrectly handled certain malformed images. If a user or automated system were tricked into opening a specially crafted image, a remote attacker could crash the application, leading to a denial of service, or possibly execute arbitrary code with user privileges.
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.