USN-3258-2: Dovecot regression

Ubuntu Security Notice USN-3258-2

11th April, 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 version:

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: https://wiki.ubuntu.com/Security/Upgrades.

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

References

CVE-2017-2669