Updated Firefox packages has been released for Ubuntu Linux:

USN-3918-2: Firefox vulnerabilities
USN-3919-1: Firefox vulnerabilities

USN-3918-2: Firefox vulnerabilities

==========================================================================
Ubuntu Security Notice USN-3918-2
March 25, 2019

firefox vulnerabilities
==========================================================================

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

- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Firefox.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

USN-3918-1 fixed vulnerabilities in Firefox. This update provides the
corresponding updates for Ubuntu 14.04 LTS.

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 via application
 crash, denial of service via successive FTP authorization prompts or modal
 alerts, trick the user with confusing permission request prompts, obtain
 sensitive information, conduct social engineering attacks, or execute
 arbitrary code. (CVE-2019-9788, CVE-2019-9789, CVE-2019-9790,
 CVE-2019-9791, CVE-2019-9792, CVE-2019-9795, CVE-2019-9796, CVE-2019-9797,
 CVE-2019-9799, CVE-2019-9802, CVE-2019-9805, CVE-2019-9806, CVE-2019-9807,
 CVE-2019-9808, CVE-2019-9809)
 
 A mechanism was discovered that removes some bounds checking for string,
 array, or typed array accesses if Spectre mitigations have been disabled.
 If a user were tricked in to opening a specially crafted website with
 Spectre mitigations disabled, an attacker could potentially exploit this
 to cause a denial of service, or execute arbitrary code. (CVE-2019-9793)
 
 It was discovered that Upgrade-Insecure-Requests was incorrectly enforced
 for same-origin navigation. An attacker could potentially exploit this to
 conduct man-in-the-middle (MITM) attacks. (CVE-2019-9803)

Update instructions:

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

Ubuntu 14.04 LTS:
  firefox  66.0.1+build1-0ubuntu0.14.04.1

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

References:
  https://usn.ubuntu.com/usn/usn-3918-2
  https://usn.ubuntu.com/usn/usn-3918-1
  CVE-2019-9788, CVE-2019-9789, CVE-2019-9790, CVE-2019-9791,
  CVE-2019-9792, CVE-2019-9793, CVE-2019-9795, CVE-2019-9796,
  CVE-2019-9797, CVE-2019-9799, CVE-2019-9802, CVE-2019-9803,
  CVE-2019-9805, CVE-2019-9806, CVE-2019-9807, CVE-2019-9808,
  CVE-2019-9809

Package Information:
 
https://launchpad.net/ubuntu/+source/firefox/66.0.1+build1-0ubuntu0.14.04.1

USN-3919-1: Firefox vulnerabilities

==========================================================================
Ubuntu Security Notice USN-3919-1
March 25, 2019

firefox vulnerabilities
==========================================================================

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

- Ubuntu 18.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 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:

Two security issues were discovered in the JavaScript engine in Firefox.
If a user were tricked in to opening a specially crafted website, an
attacker could exploit this by causing a denial of service, or executing
arbitrary code.

Update instructions:

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

Ubuntu 18.10:
firefox 66.0.1+build1-0ubuntu0.18.10.1

Ubuntu 18.04 LTS:
firefox 66.0.1+build1-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
firefox 66.0.1+build1-0ubuntu0.16.04.1

Ubuntu 14.04 LTS:
firefox 66.0.1+build1-0ubuntu0.14.04.1

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

References:
https://usn.ubuntu.com/usn/usn-3919-1
CVE-2019-9810, CVE-2019-9813

Package Information:

https://launchpad.net/ubuntu/+source/firefox/66.0.1+build1-0ubuntu0.18.10.1

https://launchpad.net/ubuntu/+source/firefox/66.0.1+build1-0ubuntu0.18.04.1

https://launchpad.net/ubuntu/+source/firefox/66.0.1+build1-0ubuntu0.16.04.1

https://launchpad.net/ubuntu/+source/firefox/66.0.1+build1-0ubuntu0.14.04.1