Mozilla has published a security advisory, highlighting a vulnerability in the following products on the 7th of December 2021. It is recommended that you take the necessary precautions by ensuring your products are always updated.
For more information on these updates, you can follow these URLs:
https://www.mozilla.org/en-US/security/advisories/mfsa2021-54/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
The Guyana National CIRT recommends that users and administrators review these updates and apply them where necessary.
PDF Download: Mozilla Security Advisory.pdf
References
https://www.cyber.gc.ca/en/alerts/mozilla-security-advisory-50