=========================================================================Ubuntu Security Notice USN-3258-2
April 11, 2017

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

- Ubuntu 16.10
- Ubuntu 16.04 LTS

Summary:

USN-3258-1 introduced a regression in Dovecot.

Software Description:
- dovecot: IMAP and POP3 email server

Details:

USN-3258-1 intended to fix a vulnerability in Dovecot. Further investigation
revealed that only Dovecot versions 2.2.26 and newer were affected by the
vulnerability. Additionally, the change introduced a regression when Dovecot
was configured to use the "dict" authentication database. This update reverts
the change. We apologize for the inconvenience.

Original advisory details:

 It was discovered that Dovecot incorrectly handled some usernames. An attacker
 could possibly use this issue to cause Dovecot to hang or crash, resulting in a
 denial of service.

Update instructions:

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

Ubuntu 16.10:
  dovecot-core                    1:2.2.24-1ubuntu1.3

Ubuntu 16.04 LTS:
  dovecot-core                    1:2.2.22-1ubuntu2.4

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

References:
  https://ubuntu.com/security/notices/USN-3258-2
  https://ubuntu.com/security/notices/USN-3258-1
  CVE-2017-2669

Package Information:
  https://launchpad.net/ubuntu/+source/dovecot/1:2.2.24-1ubuntu1.3
  https://launchpad.net/ubuntu/+source/dovecot/1:2.2.22-1ubuntu2.4