USN-4978-1: Firefox vulnerabilities

02 June 2021

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



  • firefox - Mozilla Open Source web browser


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, re-enable
camera devices without an additional permission prompt, spoof the browser
UI, or execute arbitrary code. (CVE-2021-29959, CVE-2021-29961,
CVE-2021-29966, CVE-2021-29967)

It was discovered that filenames printed from private browsing mode were
incorrectly retained in preferences. A local attacker could potentially
exploit this to obtain sensitive information. (CVE-2021-29960)

Update instructions

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

Ubuntu 21.04
Ubuntu 20.10
Ubuntu 20.04
Ubuntu 18.04

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