1. Ubuntu Security Notices
  2. USN-4926-1

USN-4926-1: Firefox vulnerabilities

Publication date

26 April 2021

Overview

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...

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

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

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
21.04 hirsute firefox –  88.0+build2-0ubuntu0.21.04.1
20.10 groovy firefox –  88.0+build2-0ubuntu0.20.10.1
20.04 focal firefox –  88.0+build2-0ubuntu0.20.04.1
18.04 bionic firefox –  88.0+build2-0ubuntu0.18.04.2
16.04 xenial firefox –  88.0+build2-0ubuntu0.16.04.1

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References

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