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USN-6591-1: Postfix vulnerability

22 January 2024

Postfix could allow bypass of email authentication if it received specially crafted network traffic.

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Releases

Packages

  • postfix - High-performance mail transport agent

Details

Timo Longin discovered that Postfix incorrectly handled certain email line
endings. A remote attacker could possibly use this issue to bypass an email
authentication mechanism, allowing domain spoofing and potential spamming.

Please note that certain configuration changes are required to address
this issue. They are not enabled by default for backward compatibility.
Information can be found at https://www.postfix.org/smtp-smuggling.html.

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

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

Ubuntu 23.10
Ubuntu 22.04
Ubuntu 20.04
Ubuntu 18.04
Ubuntu 16.04
Ubuntu 14.04

After a standard system update you need to enable
smtpd_forbid_bare_newline in your configuration and reload it to make
all the necessary changes.

Related notices

  • USN-6591-2: postfix-dev, postfix-lmdb, postfix-doc, postfix-pcre, postfix-pgsql, postfix, postfix-mysql, postfix-sqlite, postfix-cdb, postfix-ldap