USN-6591-2: Postfix update
31 January 2024
Postfix could allow bypass of email authentication if it received specially crafted network traffic.
Releases
Packages
- postfix - High-performance mail transport agent
Details
USN-6591-1 fixed vulnerabilities in Postfix. A fix with less risk of
regression has been made available since the last update. This update
updates the fix and aligns with the latest configuration guidelines
regarding this vulnerability.
We apologize for the inconvenience.
Original advisory 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.
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
-
postfix
-
3.3.0-1ubuntu0.4+esm3
Available with Ubuntu Pro
Ubuntu 16.04
-
postfix
-
3.1.0-3ubuntu0.4+esm3
Available with Ubuntu Pro
Ubuntu 14.04
-
postfix
-
2.11.0-1ubuntu1.2+esm3
Available with Ubuntu Pro
After a standard system update, you need to set
"smtpd_forbid_bare_newline = normalize" in your configuration and reload
it to make all the necessary changes.
Related notices
- USN-6591-1: postfix, postfix-mysql, postfix-dev, postfix-lmdb, postfix-pcre, postfix-sqlite, postfix-ldap, postfix-pgsql, postfix-doc, postfix-cdb