A Mailman security update has been released for Ubuntu Linux 16.04 ESM and 18.04 LTS.

USN-5121-1: Mailman vulnerabilities

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Ubuntu Security Notice USN-5121-1
October 22, 2021

mailman vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in Mailman.

Software Description:
- mailman: Web-based mailing list manager

Details:

Andre Protas, Richard Cloke, and Andy Nuttall discovered that Mailman
did not properly associate cross-site request forgery (CSRF) tokens
to specific accounts. A remote attacker could use this to perform a
CSRF attack to gain access to another account. (CVE-2021-42097)

Andre Protas, Richard Cloke, and Andy Nuttall discovered that Mailman's
cross-site request forgery (CSRF) tokens for the options page are
derived from the admin password. A remote attacker could possibly use
this to assist in performing a brute force attack against the admin
password. (CVE-2021-42096)

Update instructions:

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

Ubuntu 18.04 LTS:
mailman 1:2.1.26-1ubuntu0.4

Ubuntu 16.04 ESM:
mailman 1:2.1.20-1ubuntu0.6+esm1

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

References:
https://ubuntu.com/security/notices/USN-5121-1
CVE-2021-42096, CVE-2021-42097

Package Information:
https://launchpad.net/ubuntu/+source/mailman/1:2.1.26-1ubuntu0.4