USN-2866-1: Firefox vulnerability

8 January 2016

firefox vulnerability

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

  • Ubuntu 15.10
  • Ubuntu 15.04
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


Firefox could be made to expose sensitive information over the network.

Software Description

  • firefox - Mozilla Open Source web browser


Karthikeyan Bhargavan and Gaetan Leurent discovered that NSS incorrectly allowed MD5 to be used for TLS 1.2 connections. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information.

Update instructions

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

Ubuntu 15.10
firefox - 43.0.4+build3-0ubuntu0.15.10.1
Ubuntu 15.04
firefox - 43.0.4+build3-0ubuntu0.15.04.1
Ubuntu 14.04 LTS
firefox - 43.0.4+build3-0ubuntu0.14.04.1
Ubuntu 12.04 LTS
firefox - 43.0.4+build3-0ubuntu0.12.04.1

To update your system, please follow these instructions:

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