When loading the shared library that provides the OTR protocol...

Vulnerability Description

When loading the shared library that provides the OTR protocol implementation, Thunderbird will initially attempt to open it using a filename that isn't distributed by Thunderbird. If a computer has already been infected with a malicious library of the alternative filename, and the malicious library has been copied to a directory that is contained in the search path for executable libraries, then Thunderbird will load the incorrect library. This vulnerability affects Thunderbird < 78.9.1.

References

• https://www.mozilla.org/security/advisories/mfsa2021-13/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1682101