USN-3778-1: Firefox vulnerabilities

3 October 2018

firefox vulnerabilities

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

  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS
  • Ubuntu 14.04 LTS


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


A crash was discovered in TransportSecurityInfo used for SSL, which could be triggered by data stored in the local cache directory. An attacker could potentially exploit this in combination with another vulnerability that allowed them to write data to the cache, to execute arbitrary code. (CVE-2018-12385)

A type confusion bug was discovered in JavaScript. If a user were tricked in to opening a specially crafted website, an attacker could exploit this to cause a denial of service, or execute arbitrary code. (CVE-2018-12386)

It was discovered that the Array.prototype.push could leak memory addresses to the calling function in some circumstances. An attacker could exploit this in combination with another vulnerability to help execute arbitrary code. (CVE-2018-12387)

Update instructions

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

Ubuntu 18.04 LTS
firefox - 62.0.3+build1-0ubuntu0.18.04.1
Ubuntu 16.04 LTS
firefox - 62.0.3+build1-0ubuntu0.16.04.2
Ubuntu 14.04 LTS
firefox - 62.0.3+build1-0ubuntu0.14.04.2

To update your system, please follow these instructions:

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