A Firefox security update has been released for Ubuntu Linux 18.04 LTS, 20.04 LTS, and 21.10.

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Ubuntu Security Notice USN-5434-1
May 23, 2022

firefox vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Firefox could be made to execute JavaScript in a privileged context if it
opened a malicious website.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

It was discovered that the methods of an Array object could be corrupted
as a result of prototype pollution by sending a message to the parent
process. If a user were tricked into opening a specially crafted website,
an attacker could exploit this to execute JavaScript in a privileged
context.

Update instructions:

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

Ubuntu 21.10:
firefox 100.0.2+build1-0ubuntu0.21.10.1

Ubuntu 20.04 LTS:
firefox 100.0.2+build1-0ubuntu0.20.04.1

Ubuntu 18.04 LTS:
firefox 100.0.2+build1-0ubuntu0.18.04.1

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

References:
  https://ubuntu.com/security/notices/USN-5434-1
CVE-2022-1529, CVE-2022-1802

Package Information:
  https://launchpad.net/ubuntu/+source/firefox/100.0.2+build1-0ubuntu0.21.10.1
  https://launchpad.net/ubuntu/+source/firefox/100.0.2+build1-0ubuntu0.20.04.1
  https://launchpad.net/ubuntu/+source/firefox/100.0.2+build1-0ubuntu0.18.04.1