[USN-5186-2] Firefox regressions

========================================================================== Ubuntu Security Notice USN-5186-2 December 20, 2021
firefox regressions ==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 21.10 – Ubuntu 21.04 – Ubuntu 20.04 LTS – Ubuntu 18.04 LTS
Summary:
USN-5186-1 caused some minor regressions in Firefox.
Software Description: – firefox: Mozilla Open Source web browser
Details:
USN-5186-1 fixed vulnerabilities in Firefox. The update introduced several minor regressions. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, conduct spoofing attacks, bypass CSP restrictions, or execute arbitrary code. (CVE-2021-43536, CVE-2021-43537, CVE-2021-43538, CVE-2021-43539, CVE-2021-43541, CVE-2021-43542, CVE-2021-43543, CVE-2021-43545, CVE-2021-43546) A security issue was discovered with the handling of WebExtension permissions. If a user were tricked into installing a specially crafted extension, an attacker could potentially exploit this to create and install a service worker that wouldn’t be uninstalled with the extension. (CVE-2021-43540)
Update instructions:
The problem can be corrected by updating your system to the following package versions:
Ubuntu 21.10: firefox 95.0.1+build2-0ubuntu0.21.10.1
Ubuntu 21.04: firefox 95.0.1+build2-0ubuntu0.21.04.1
Ubuntu 20.04 LTS: firefox 95.0.1+build2-0ubuntu0.20.04.1
Ubuntu 18.04 LTS: firefox 95.0.1+build2-0ubuntu0.18.04.1
After a standard system update you need to restart Firefox to make all the necessary changes.
References: ubuntu.com/security/notices/USN-5186-2 ubuntu.com/security/notices/USN-5186-1 launchpad.net/bugs/1955433
Package Information:
launchpad.net/ubuntu/+source/firefox/95.0.1+build2-0ubuntu0.21.10.1
launchpad.net/ubuntu/+source/firefox/95.0.1+build2-0ubuntu0.21.04.1
launchpad.net/ubuntu/+source/firefox/95.0.1+build2-0ubuntu0.20.04.1
launchpad.net/ubuntu/+source/firefox/95.0.1+build2-0ubuntu0.18.04.1