USN-2672-1: NSS vulnerabilities

9 July 2015

nss vulnerabilities

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

  • Ubuntu 15.04
  • Ubuntu 14.10
  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


Several security issues were fixed in NSS.

Software Description

  • nss - Network Security Service library


Karthikeyan Bhargavan discovered that NSS incorrectly handled state transitions for the TLS state machine. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to skip the ServerKeyExchange message and remove the forward-secrecy property. (CVE-2015-2721)

Watson Ladd discovered that NSS incorrectly handled Elliptical Curve Cryptography (ECC) multiplication. A remote attacker could possibly use this issue to spoof ECDSA signatures. (CVE-2015-2730)

As a security improvement, this update modifies NSS behaviour to reject DH key sizes below 768 bits, preventing a possible downgrade attack.

This update also refreshes the NSS package to version 3.19.2 which includes the latest CA certificate bundle.

Update instructions

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

Ubuntu 15.04
libnss3 - 2:3.19.2-0ubuntu15.04.1
Ubuntu 14.10
libnss3 - 2:3.19.2-0ubuntu0.14.10.1
Ubuntu 14.04 LTS
libnss3 - 2:3.19.2-0ubuntu0.14.04.1
Ubuntu 12.04 LTS
libnss3 - 3.19.2-0ubuntu0.12.04.1

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.