A firefox-esr security update has been released for Debian GNU/Linux 11 to address multiple security issues.

DSA 5237-1: firefox-esr security update

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Debian Security Advisory DSA-5237-1 security@debian.org
  https://www.debian.org/security/ Moritz Muehlenhoff
September 23, 2022   https://www.debian.org/security/faq
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Package : firefox-esr
CVE ID : CVE-2022-40956 CVE-2022-40957 CVE-2022-40958 CVE-2022-40959
CVE-2022-40960 CVE-2022-40962

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

Debian follows the extended support releases (ESR) of Firefox. Support
for the 91.x series has ended, so starting with this update we're now
following the 102.x releases.

Between 91.x and 102.x, Firefox has seen a number of feature updates.
For more information please refer to
  https://www.mozilla.org/en-US/firefox/102.0esr/releasenotes/

For the stable distribution (bullseye), these problems have been fixed in
version 102.3.0esr-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/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/