USN-3029-1: NSS vulnerability

11 July 2016

nss vulnerability

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

  • Ubuntu 16.04 LTS
  • Ubuntu 15.10
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


NSS could be made to crash or run programs if it processed specially crafted network traffic.

Software Description

  • nss - Network Security Service library


Tyson Smith and Jed Davis discovered that NSS incorrectly handled memory. A remote attacker could use this issue to cause NSS to crash, resulting in a denial of service, or possibly execute arbitrary code.

This update refreshes the NSS package to version 3.23 which includes the latest CA certificate bundle. As a security improvement, this update also modifies NSS behaviour to reject DH key sizes below 1024 bits, preventing a possible downgrade attack.

Update instructions

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

Ubuntu 16.04 LTS
libnss3 - 2:3.23-0ubuntu0.16.04.1
Ubuntu 15.10
libnss3 - 2:3.23-0ubuntu0.15.10.1
Ubuntu 14.04 LTS
libnss3 - 2:3.23-0ubuntu0.14.04.1
Ubuntu 12.04 LTS
libnss3 - 2:3.23-0ubuntu0.12.04.1

To update your system, please follow these instructions:

This update uses a new upstream release, which includes additional bug fixes. After a standard system update you need to restart any applications that use NSS, such as Evolution and Chromium, to make all the necessary changes.