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             AUSCERT External Security Bulletin Redistribution

                    USN-4926-1: Firefox vulnerabilities
                               27 April 2021


        AusCERT Security Bulletin Summary

Product:           Firefox
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Execute Arbitrary Code/Commands -- Remote with User Interaction
                   Increased Privileges            -- Remote with User Interaction
                   Denial of Service               -- Remote with User Interaction
                   Provide Misleading Information  -- Remote with User Interaction
                   Access Confidential Data        -- Remote with User Interaction
                   Reduced Security                -- Remote with User Interaction
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-29947 CVE-2021-29946 CVE-2021-29945
                   CVE-2021-24002 CVE-2021-24001 CVE-2021-24000
                   CVE-2021-23999 CVE-2021-23998 CVE-2021-23997
                   CVE-2021-23996 CVE-2021-23995 CVE-2021-23994

Reference:         ESB-2021.1393

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

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.

  o Ubuntu 21.04
  o Ubuntu 20.10
  o Ubuntu 20.04 LTS
  o Ubuntu 18.04 LTS
  o Ubuntu 16.04 LTS


  o 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, 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

Ubuntu 21.04

  o firefox - 88.0+build2-0ubuntu0.21.04.1

Ubuntu 20.10

  o firefox - 88.0+build2-0ubuntu0.20.10.1

Ubuntu 20.04

  o firefox - 88.0+build2-0ubuntu0.20.04.1

Ubuntu 18.04

  o firefox - 88.0+build2-0ubuntu0.18.04.2

Ubuntu 16.04

  o firefox - 88.0+build2-0ubuntu0.16.04.1

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


  o CVE-2021-24000
  o CVE-2021-23996
  o CVE-2021-23997
  o CVE-2021-23995
  o CVE-2021-29946
  o CVE-2021-23999
  o CVE-2021-23994
  o CVE-2021-23998
  o CVE-2021-29945
  o CVE-2021-24001
  o CVE-2021-24002
  o CVE-2021-29947

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