A Dovecot security update has been released for Ubuntu 14.04 ESM.

USN-4674-2: Dovecot vulnerability

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Ubuntu Security Notice USN-4674-2
January 04, 2021

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

- Ubuntu 14.04 ESM

Summary:

Dovecot could be made to denial of service if it received a specially
crafted MIME.

Software Description:
- dovecot: IMAP and POP3 email server

Details:

USN-4674-1 fixed a vulnerability in Dovecot. This update provides
the corresponding update for Ubuntu 14.04 ESM.

Original advisory details:

Innokentii Sennovskiy discovered that Dovecot incorrectly handled MIME
parsing. A remote attacker could possibly use this issue to cause Dovecot
to crash, resulting in a denial of service. (CVE-2020-25275)

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+esm4

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

References:
  https://usn.ubuntu.com/4674-2
  https://usn.ubuntu.com/4674-1
CVE-2020-25275