USN-4926-1: Firefox vulnerabilities

26 April 2021

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

Releases

Packages

  • firefox - Mozilla Open Source web browser

Details

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, spoof the
browser UI, bypass security restrictions, trick the user into disclosing
confidential information, or execute arbitrary code. (CVE-2021-23994,
CVE-2021-23996, CVE-2021-23997, CVE-2021-23998, CVE-2021-23999,
CVE-2021-24000, CVE-2021-24001, CVE-2021-29945, CVE-2021-29946,
CVE-2021-29947)

A use-after-free was discovered when Responsive Design Mode was
enabled. If a user were tricked into opening a specially crafted
website with Responsive Design Mode enabled, an attacker could
potentially exploit this to cause a denial of service, or execute
arbitrary code. (CVE-2021-23995)

It was discovered that Firefox mishandled ftp URLs with encoded newline
characters. If a user were tricked into clicking on a specially crafted
link, an attacker could potentially exploit this to send arbitrary
FTP commands. (CVE-2021-24002)

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
Ubuntu 16.04

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