USN-4323-1: Firefox vulnerabilities

7 April 2020

firefox vulnerabilities

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

  • Ubuntu 19.10
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS


Firefox could be made to crash or run programs as your login if it opened a malicious website.

Software Description

  • firefox - Mozilla Open Source web browser


Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, or execute arbitrary code. (CVE-2020-6821, CVE-2020-6822, CVE-2020-6824, CVE-2020-6825, CVE-2020-6826)

It was discovered that extensions could obtain auth codes from OAuth login flows in some circumstances. If a user were tricked in to installing a specially crafted extension, an attacker could potentially exploit this to obtain access to the user’s account. (CVE-2020-6823)

Update instructions

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

Ubuntu 19.10
firefox - 75.0+build3-0ubuntu0.19.10.1
Ubuntu 18.04 LTS
firefox - 75.0+build3-0ubuntu0.18.04.1
Ubuntu 16.04 LTS
firefox - 75.0+build3-0ubuntu0.16.04.1

To update your system, please follow these instructions:

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