USN-2821-1: GnuTLS vulnerability

30 November 2015

gnutls26 vulnerability

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

  • Ubuntu 14.04 LTS
  • Ubuntu 12.04 LTS


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

Software Description

  • gnutls26 - GNU TLS library


It was discovered that GnuTLS incorrectly validated the first byte of padding in CBC modes. A remote attacker could possibly use this issue to perform a padding oracle attack.

Update instructions

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

Ubuntu 14.04 LTS
libgnutls26 - 2.12.23-12ubuntu2.3
Ubuntu 12.04 LTS
libgnutls26 - 2.12.14-5ubuntu3.10

To update your system, please follow these instructions:

In general, a standard system update will make all the necessary changes.