Mozilla has published security advisories, highlighting vulnerabilities in Firefox, Firefox ESR and Thunderbird on 16th December, 2020. 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 these URLs:
https://www.mozilla.org/en-US/security/advisories/mfsa2020-54/
https://www.mozilla.org/en-US/security/advisories/mfsa2020-55/
https://www.mozilla.org/en-US/security/advisories/mfsa2020-56/
The Guyana National CIRT recommends that users and administrators review these updates and apply them where necessary.
References