USN-8253-2: Postfix vulnerability

Publication date

3 June 2026

Overview

Postfix could be made to crash if it received specially crafted network traffic.


Packages

  • postfix - High-performance mail transport agent

Details

USN-8253-1 fixed a vulnerability in Postfix. This update provides the
corresponding fix for Postfix on Ubuntu 14.04 LTS, Ubuntu 16.04 LTS,
Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS.

Original advisory details:

Kamil Frankowicz discovered that Postfix incorrectly handled certain
enhanced status codes. A remote attacker could possibly use this issue to
cause Postfix to crash, resulting in a denial of service.

USN-8253-1 fixed a vulnerability in Postfix. This update provides the
corresponding fix for Postfix on Ubuntu 14.04 LTS, Ubuntu 16.04 LTS,
Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS.

Original advisory details:

Kamil Frankowicz discovered that Postfix incorrectly handled certain
enhanced status codes. A remote attacker could possibly use this issue to
cause Postfix to crash, resulting in a denial of service.

Update instructions

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

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
20.04 LTS focal postfix –  3.4.13-0ubuntu1.4+esm1  
18.04 LTS bionic postfix –  3.3.0-1ubuntu0.4+esm4  
16.04 LTS xenial postfix –  3.1.0-3ubuntu0.4+esm4  
14.04 LTS trusty postfix –  2.11.0-1ubuntu1.2+esm4  

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