Several security issues were fixed in Thunderbird.
It was discovered that encrypted S/MIME parts in a multipart message can leak plaintext contents when included in a HTML reply or forward in some circumstances. If a user were tricked in to replying to or forwarding a specially crafted message, an attacker could potentially exploit this to obtain sensitive information. (CVE-2019-11739)
8 October 2019
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in Thunderbird.
It was discovered that encrypted S/MIME parts in a multipart message can leak plaintext contents when included in a HTML reply or forward in some circumstances. If a user were tricked in to replying to or forwarding a specially crafted message, an attacker could potentially exploit this to obtain sensitive information. (CVE-2019-11739)
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 obtain sensitive information, conduct cross-site scripting (XSS) attack, scause a denial of service, or execute arbitrary code. (CVE-2019-11740, CVE-2019-11742, CVE-2019-11743, CVE-2019-11744, CVE-2019-11746, CVE-2019-11752)
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.
Vulmon