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USN-5321-3: Firefox regressions

24 March 2022

USN-5321-1 introduced minor regressions in Firefox.



  • firefox - Mozilla Open Source web browser


USN-5321-1 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, spoof the browser
UI, bypass security restrictions, obtain sensitive information, or execute
arbitrary code. (CVE-2022-0843, CVE-2022-26381, CVE-2022-26382,
CVE-2022-26383, CVE-2022-26384, CVE-2022-26385)

A TOCTOU bug was discovered when verifying addon signatures during
install. A local attacker could potentially exploit this to trick a
user into installing an addon with an invalid signature.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 21.10
Ubuntu 20.04
Ubuntu 18.04

After a standard system update you need to restart Firefox to make
all the necessary changes.