USN-4353-1: Firefox vulnerabilities

7 May 2020

firefox vulnerabilities

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

  • Ubuntu 20.04 LTS
  • 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, bypass security restrictions, spoof the URL bar, or execute arbitrary code. (CVE-2020-6831, CVE-2020-12387, CVE-2020-12390, CVE-2020-12391, CVE-2020-12394, CVE-2020-12395, CVE-2020-12396)

It was discovered that the Devtools’ ‘Copy as cURL’ feature did not properly escape the HTTP POST data of a request. If a user were tricked in to using the ‘Copy as cURL’ feature to copy and paste a command with specially crafted data in to a terminal, an attacker could potentially exploit this to obtain sensitive information from local files. (CVE-2020-12392)

Update instructions

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

Ubuntu 20.04 LTS
firefox - 76.0+build2-0ubuntu0.20.04.1
Ubuntu 19.10
firefox - 76.0+build2-0ubuntu0.19.10.1
Ubuntu 18.04 LTS
firefox - 76.0+build2-0ubuntu0.18.04.1
Ubuntu 16.04 LTS
firefox - 76.0+build2-0ubuntu0.16.04.1

To update your system, please follow these instructions:

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