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Ubuntu Security Notice USN-6509-2
December 04, 2023

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

- Ubuntu 20.04 LTS

Summary:

USN-6509-1 caused some minor regressions in Firefox.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

USN-6509-1 fixed vulnerabilities in Firefox. The update introduced
several minor regressions. This update fixes the problem.

We apologize for the inconvenience.

Original advisory 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, obtain sensitive
  information across domains, or execute arbitrary code. (CVE-2023-6206,
  CVE-2023-6210, CVE-2023-6211, CVE-2023-6212, CVE-2023-6213)
  
  It was discovered that Firefox did not properly manage memory when
  images were created on the canvas element. An attacker could potentially
  exploit this issue to obtain sensitive information. (CVE-2023-6204)
  
  It discovered that Firefox incorrectly handled certain memory when using a
  MessagePort. An attacker could potentially exploit this issue to cause a
  denial of service. (CVE-2023-6205)
  
  It discovered that Firefox incorrectly did not properly manage ownership
  in ReadableByteStreams. An attacker could potentially exploit this issue
  to cause a denial of service. (CVE-2023-6207)
  
  It discovered that Firefox incorrectly did not properly manage copy
  operations when using Selection API in X11. An attacker could potentially
  exploit this issue to obtain sensitive information. (CVE-2023-6208)
  
  Rachmat Abdul Rokhim discovered incorrectly handled parsing of relative
  URLS starting with "///". An attacker could potentially exploit this issue
  to cause a denial of service. (CVE-2023-6209)

Update instructions:

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

Ubuntu 20.04 LTS:
   firefox                         120.0.1+build1-0ubuntu0.20.04.1

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

References:
   https://ubuntu.com/security/notices/USN-6509-2
   https://ubuntu.com/security/notices/USN-6509-1
   https://launchpad.net/bugs/2045518

Package Information:
   https://launchpad.net/ubuntu/+source/firefox/120.0.1+build1-0ubuntu0.20.04.1