Ubuntu Security Notice USN-3881-2

Ubuntu Security Notice USN-3881-2
Ubuntu Security Notice 3881-2 – USN-3881-1 fixed a vulnerability in Dovecot. This update provides the corresponding update for Ubuntu 12.04 ESM. It was discovered that Dovecot incorrectly handled client certificates. A remote attacker in possession of a valid certificate with an empty username field could possibly use this issue to impersonate other users. Various other issues were also addressed.