Updated Dovecot packages has been released for Ubuntu Linux:

USN-4110-1: Dovecot vulnerability
USN-4110-2: Dovecot vulnerability

USN-4110-1: Dovecot vulnerability

=========================================================================
Ubuntu Security Notice USN-4110-1
August 28, 2019

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

- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Dovecot could be made to crash or execute arbitrary code if it
received a specially crafted data.

Software Description:
- dovecot: IMAP and POP3 email server

Details:

Nick Roessler and Rafi Rubin discovered that Dovecot incorrectly
handled certain data. An attacker could possibly use this issue
to cause a denial of service or execute arbitrary code.

Update instructions:

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

Ubuntu 19.04:
dovecot-core 1:2.3.4.1-1ubuntu2.3

Ubuntu 18.04 LTS:
dovecot-core 1:2.2.33.2-1ubuntu4.4

Ubuntu 16.04 LTS:
dovecot-core 1:2.2.22-1ubuntu2.11

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

References:
https://usn.ubuntu.com/4110-1
CVE-2019-11500

Package Information:
https://launchpad.net/ubuntu/+source/dovecot/1:2.3.4.1-1ubuntu2.3
https://launchpad.net/ubuntu/+source/dovecot/1:2.2.33.2-1ubuntu4.4
https://launchpad.net/ubuntu/+source/dovecot/1:2.2.22-1ubuntu2.11

USN-4110-2: Dovecot vulnerability

=========================================================================
Ubuntu Security Notice USN-4110-2
August 28, 2019

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

- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

Dovecot could be made to crash or execute arbitrary code if it received
a specially crafted data.

Software Description:
- dovecot: IMAP and POP3 email server

Details:

USN-4110-1 fixed a vulnerability in Dovecot. This update provides
the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM.

Original advisory details:

Nick Roessler and Rafi Rubin discovered that Dovecot incorrectly
handled certain data. An attacker could possibly use this issue
to cause a denial of service or execute arbitrary code.

Update instructions:

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

Ubuntu 14.04 ESM:
dovecot-core 1:2.2.9-1ubuntu2.6+esm1

Ubuntu 12.04 ESM:
dovecot-core 1:2.0.19-0ubuntu2.7

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

References:
https://usn.ubuntu.com/4110-2
https://usn.ubuntu.com/4110-1
CVE-2019-11500