USN-1752-1: GnuTLS vulnerability

Ubuntu Security Notice USN-1752-1

27th February, 2013

gnutls13, gnutls26 vulnerability

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

  • Ubuntu 12.10
  • Ubuntu 12.04 LTS
  • Ubuntu 11.10
  • Ubuntu 10.04 LTS
  • Ubuntu 8.04 LTS


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

Software description

  • gnutls13 - GNU TLS library
  • gnutls26 - GNU TLS library


Nadhem Alfardan and Kenny Paterson discovered that the TLS protocol as used
in GnuTLS was vulnerable to a timing side-channel attack known as the
"Lucky Thirteen" issue. A remote attacker could use this issue to perform
plaintext-recovery attacks via analysis of timing data.

Update instructions

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

Ubuntu 12.10:
libgnutls26 2.12.14-5ubuntu4.2
Ubuntu 12.04 LTS:
libgnutls26 2.12.14-5ubuntu3.2
Ubuntu 11.10:
libgnutls26 2.10.5-1ubuntu3.3
Ubuntu 10.04 LTS:
libgnutls26 2.8.5-2ubuntu0.3
Ubuntu 8.04 LTS:
libgnutls13 2.0.4-1ubuntu2.9

To update your system, please follow these instructions:

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