=========================================================================Ubuntu Security Notice USN-2540-1
March 23, 2015

gnutls26, gnutls28 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 14.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS
- Ubuntu 10.04 LTS

Summary:

Several security issues were fixed in GnuTLS.

Software Description:
- gnutls28: GNU TLS library
- gnutls26: GNU TLS library

Details:

It was discovered that GnuTLS did not perform date and time checks on
CA certificates, contrary to expectations. This issue only affected
Ubuntu 10.04 LTS. (CVE-2014-8155)

Nikos Mavrogiannopoulos discovered that GnuTLS incorrectly verified that
signature algorithms matched. A remote attacker could possibly use this
issue to downgrade to a disallowed algorithm. This issue only affected
Ubuntu 10.04 LTS, Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2015-0282)

It was discovered that GnuTLS incorrectly verified certificate algorithms.
A remote attacker could possibly use this issue to downgrade to a
disallowed algorithm. (CVE-2015-0294)

Update instructions:

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

Ubuntu 14.10:
  libgnutls-deb0-28               3.2.16-1ubuntu2.2

Ubuntu 14.04 LTS:
  libgnutls26                     2.12.23-12ubuntu2.2

Ubuntu 12.04 LTS:
  libgnutls26                     2.12.14-5ubuntu3.9

Ubuntu 10.04 LTS:
  libgnutls26                     2.8.5-2ubuntu0.7

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

References:
  https://ubuntu.com/security/notices/USN-2540-1
  CVE-2014-8155, CVE-2015-0282, CVE-2015-0294

Package Information:
  https://launchpad.net/ubuntu/+source/gnutls28/3.2.16-1ubuntu2.2
  https://launchpad.net/ubuntu/+source/gnutls26/2.12.23-12ubuntu2.2
  https://launchpad.net/ubuntu/+source/gnutls26/2.12.14-5ubuntu3.9
  https://launchpad.net/ubuntu/+source/gnutls26/2.8.5-2ubuntu0.7