Several security issues were fixed in Thunderbird.
Multiple security issues were discovered in Thunderbird. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, bypass same-origin restrictions, or execute arbitrary code.
24 January 2019
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in Thunderbird.
Multiple security issues were discovered in Thunderbird. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, bypass same-origin restrictions, or 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.
After a standard system update you need to restart Thunderbird to make all the necessary changes.