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

USN-4353-2: Firefox regression

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Ubuntu Security Notice USN-4353-2
May 12, 2020

firefox regression
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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:

USN-4353-1 caused a regression in Firefox.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

USN-4353-1 fixed vulnerabilities in Firefox. The update caused a
regression that impaired the functionality of some addons. 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 in to opening a specially crafted website, an attacker could
potentially exploit these to cause a denial of service, bypass security
restrictions, spoof the URL bar, or execute arbitrary code.
(CVE-2020-6831, CVE-2020-12387, CVE-2020-12390, CVE-2020-12391,
CVE-2020-12394, CVE-2020-12395, CVE-2020-12396)
It was discovered that the Devtools’ ‘Copy as cURL’ feature did not
properly HTTP POST data of a request. If a user were tricked in to using
the ‘Copy as cURL’ feature to copy and paste a command with specially
crafted data in to a terminal, an attacker could potentially exploit this
to obtain sensitive information from local files.
(CVE-2020-12392)

Update instructions:

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

Ubuntu 20.04 LTS:
firefox 76.0.1+build1-0ubuntu0.20.04.1

Ubuntu 19.10:
firefox 76.0.1+build1-0ubuntu0.19.10.1

Ubuntu 18.04 LTS:
firefox 76.0.1+build1-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
firefox 76.0.1+build1-0ubuntu0.16.04.1

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

References:
  https://usn.ubuntu.com/4353-2
  https://usn.ubuntu.com/4353-1
  https://launchpad.net/bugs/1878251

Package Information:

  https://launchpad.net/ubuntu/+source/firefox/76.0.1+build1-0ubuntu0.20.04.1

  https://launchpad.net/ubuntu/+source/firefox/76.0.1+build1-0ubuntu0.19.10.1

  https://launchpad.net/ubuntu/+source/firefox/76.0.1+build1-0ubuntu0.18.04.1

  https://launchpad.net/ubuntu/+source/firefox/76.0.1+build1-0ubuntu0.16.04.1