USN-4299-1: Firefox vulnerabilities

11 March 2020

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 in to opening a specially crafted website, an attacker could
potentially exploit these to cause a denial of service, spoof the URL or
other browser chrome, obtain sensitive information, bypass Content
Security Policy (CSP) protections, or execute arbitrary code.
(CVE-2019-20503, CVE-2020-6805, CVE-2020-6806, CVE-2020-6807,
CVE-2020-6808, CVE-2020-6810, CVE-2020-6812, CVE-2020-6813, CVE-2020-6814,

It was discovered that Web Extensions with the all-url permission could
access local files. If a user were tricked in to installing a specially
crafted extension, an attacker could potentially exploit this to obtain
sensitive information. (CVE-2020-6809)

It was discovered that the Devtools' 'Copy as cURL' feature did not fully
escape website-controlled data. 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
execute arbitrary commands via command injection. (CVE-2020-6811)

Update instructions

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

Ubuntu 19.10
Ubuntu 18.04
Ubuntu 16.04

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