[USN-4110-4] Dovecot regression

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Ubuntu Security Notice USN-4110-4
August 28, 2019

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

- Ubuntu 14.04 ESM
- Ubuntu 12.04 ESM

Summary:

USN-4110-1 introduced a regression in Dovecot.

Software Description:
- dovecot: IMAP and POP3 email server

Details:

USN-4110-1 fixed a vulnerability in Dovecot. The update introduced
a regression causing a wrong check. This update fixes the problem for
Ubuntu 12.04 ESM and Ubuntu 14.04 ESM.

We apologize for the inconvenience.

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+esm2

Ubuntu 12.04 ESM:
dovecot-core 1:2.0.19-0ubuntu2.8

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

References:
https://usn.ubuntu.com/4110-4
https://usn.ubuntu.com/4110-1
CVE-2019-11500