A Firefox security update has been released for Ubuntu Linux 20.04 LTS, 19.10, 18.04 LTS, and 16.04 LTS.

USN-4423-1: Firefox vulnerability

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Ubuntu Security Notice USN-4423-1
July 14, 2020

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

- Ubuntu 20.04 LTS
- Ubuntu 19.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

A X-Frame-Options bypass was discovered in Firefox.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

It was discovered that X-Frame-Options could be bypassed in some
circumstances. If a user were tricked in to opening a specially crafted
website, an attacker could potentially exploit this to conduct
clickjacking attacks.

Update instructions:

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

Ubuntu 20.04 LTS:
firefox 78.0.2+build2-0ubuntu0.20.04.1

Ubuntu 19.10:
firefox 78.0.2+build2-0ubuntu0.19.10.1

Ubuntu 18.04 LTS:
firefox 78.0.2+build2-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
firefox 78.0.2+build2-0ubuntu0.16.04.1

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

References:
  https://usn.ubuntu.com/4423-1
  https://launchpad.net/bugs/1887576

Package Information:

  https://launchpad.net/ubuntu/+source/firefox/78.0.2+build2-0ubuntu0.20.04.1

  https://launchpad.net/ubuntu/+source/firefox/78.0.2+build2-0ubuntu0.19.10.1

  https://launchpad.net/ubuntu/+source/firefox/78.0.2+build2-0ubuntu0.18.04.1

  https://launchpad.net/ubuntu/+source/firefox/78.0.2+build2-0ubuntu0.16.04.1