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

USN-4406-1: Mailman vulnerability

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Ubuntu Security Notice USN-4406-1
June 29, 2020

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

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Mailman could be made to inject arbitrary content in the login page if it
received a specially crafted input.

Software Description:
- mailman: Web-based mailing list manager (legacy branch)

Details:

It was discovered that Mailman incorrectly handled certain inputs.
An attacker could possibly use this issue to inject arbitrary content
in the login page.

Update instructions:

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

Ubuntu 18.04 LTS:
mailman 1:2.1.26-1ubuntu0.3

Ubuntu 16.04 LTS:
mailman 1:2.1.20-1ubuntu0.6

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

References:
https://usn.ubuntu.com/4406-1
CVE-2020-15011

Package Information:
https://launchpad.net/ubuntu/+source/mailman/1:2.1.26-1ubuntu0.3
https://launchpad.net/ubuntu/+source/mailman/1:2.1.20-1ubuntu0.6