=========================================================================Ubuntu Security Notice USN-3918-4
April 16, 2019

firefox regressions
=========================================================================
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:

USN-3918-1 caused a regression in Firefox.

Software Description:
- firefox: Mozilla Open Source web browser

Details:

USN-3918-1 fixed vulnerabilities in Firefox. The update caused web
compatibility and performance issues with some websites. 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 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 18.10:
  firefox                         66.0.3+build1-0ubuntu0.18.10.1

Ubuntu 18.04 LTS:
  firefox                         66.0.3+build1-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
  firefox                         66.0.3+build1-0ubuntu0.16.04.1

Ubuntu 14.04 LTS:
  firefox                         66.0.3+build1-0ubuntu0.14.04.1

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

References:
  https://ubuntu.com/security/notices/USN-3918-4
  https://ubuntu.com/security/notices/USN-3918-1
  https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1825051

Package Information:
 
https://launchpad.net/ubuntu/+source/firefox/66.0.3+build1-0ubuntu0.18.10.1
 
https://launchpad.net/ubuntu/+source/firefox/66.0.3+build1-0ubuntu0.18.04.1
 
https://launchpad.net/ubuntu/+source/firefox/66.0.3+build1-0ubuntu0.16.04.1
 
https://launchpad.net/ubuntu/+source/firefox/66.0.3+build1-0ubuntu0.14.04.1