=========================================================================Ubuntu Security Notice USN-2821-1
November 30, 2015

gnutls26 vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

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

Software Description:
- gnutls26: GNU TLS library

Details:

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

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

References:
  
  https://bugs.launchpad.net/ubuntu/+source/gnutls26/+bug/1510163

Package Information:
  https://launchpad.net/ubuntu/+source/gnutls26/2.12.23-12ubuntu2.3
  https://launchpad.net/ubuntu/+source/gnutls26/2.12.14-5ubuntu3.10