Mozilla has published a security advisory, highlighting vulnerabilities in Thunderbird on 12th August 2021. It is recommended that you take the necessary precautions by ensuring your products are always updated.
For more information on these Mozilla updates, you can follow this URL:
https://www.mozilla.org/en-US/security/advisories/mfsa2021-36/
The Guyana National CIRT recommends that users and administrators review these updates and apply them where necessary.
PDF Download: Mozilla Release Security Updates for Thunderbird.pdf
References