Debian Bullseye and Buster: Critical Code Execution Risk in Firefox-Esr

Multiple security issues have been found in the Mozilla Firefox web
browser, which could potentially result in the execution of arbitrary
code.

For the oldstable distribution (buster), these problems have been fixed
in version 78.15.0esr-1~deb10u1.

For the stable distribution (bullseye), these problems have been fixed in
version 78.15.0esr-1~deb11u1.

We recommend that you upgrade your firefox-esr packages.

For the detailed security status of firefox-esr please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/firefox-esr

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/