USN-3258-2: Dovecot regression

11 April 2017

dovecot regression

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

  • Ubuntu 16.10
  • Ubuntu 16.04 LTS


USN-3258-1 introduced a regression in Dovecot.

Software Description

  • dovecot - IMAP and POP3 email server


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

To update your system, please follow these instructions:

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