Updated Firefox packages has been released for Ubuntu Linux 19.10, 18.04 LTS, and 16.04 LTS.

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Ubuntu Security Notice USN-4299-1
March 11, 2020

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

- Ubuntu 19.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Firefox could be made to crash or run programs as your login if it
opened a malicious website.

Software Description:
- firefox: Mozilla Open Source web browser

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, spoof the URL or
other browser chrome, obtain sensitive information, bypass Content
Security Policy (CSP) protections, or execute arbitrary code.
(CVE-2019-20503, CVE-2020-6805, CVE-2020-6806, CVE-2020-6807,
CVE-2020-6808, CVE-2020-6810, CVE-2020-6812, CVE-2020-6813, CVE-2020-6814,
CVE-2020-6815)

It was discovered that Web Extensions with the all-url permission could
access local files. If a user were tricked in to installing a specially
crafted extension, an attacker could potentially exploit this to obtain
sensitive information. (CVE-2020-6809)

It was discovered that the Devtools' 'Copy as cURL' feature did not fully
escape website-controlled data. 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
execute arbitrary commands via command injection. (CVE-2020-6811)

Update instructions:

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

Ubuntu 19.10:
firefox 74.0+build3-0ubuntu0.19.10.1

Ubuntu 18.04 LTS:
firefox 74.0+build3-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
firefox 74.0+build3-0ubuntu0.16.04.1

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

References:
https://usn.ubuntu.com/4299-1
CVE-2019-20503, CVE-2020-6805, CVE-2020-6806, CVE-2020-6807,
CVE-2020-6808, CVE-2020-6809, CVE-2020-6810, CVE-2020-6811,
CVE-2020-6812, CVE-2020-6813, CVE-2020-6814, CVE-2020-6815

Package Information:
https://launchpad.net/ubuntu/+source/firefox/74.0+build3-0ubuntu0.19.10.1
https://launchpad.net/ubuntu/+source/firefox/74.0+build3-0ubuntu0.18.04.1
https://launchpad.net/ubuntu/+source/firefox/74.0+build3-0ubuntu0.16.04.1