A RedCloth security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, 22.04 LTS and 23.04.

[USN-6358-1] RedCloth vulnerability

==========================================================================
Ubuntu Security Notice USN-6358-1
September 12, 2023

ruby-redcloth vulnerability
==========================================================================

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

- Ubuntu 23.04
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)

Summary:

RedCloth could be made to crash if it received specially crafted
input.

Software Description:
- ruby-redcloth: Textile module for Ruby

Details:

It was discovered that RedCloth incorrectly handled certain inputs during
html sanitisation. An attacker could possibly use this issue to cause a
denial of service.

Update instructions:

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

Ubuntu 23.04:
ruby-redcloth 4.3.2-4ubuntu0.23.04.1

Ubuntu 22.04 LTS:
ruby-redcloth 4.3.2-4ubuntu0.22.04.1

Ubuntu 20.04 LTS:
ruby-redcloth 4.3.2-3+deb10u1build0.20.04.1

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
ruby-redcloth 4.3.2-3ubuntu0.1~esm1

Ubuntu 16.04 LTS (Available with Ubuntu Pro):
ruby-redcloth 4.2.9-5ubuntu0.1~esm1

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

References:
https://ubuntu.com/security/notices/USN-6358-1
CVE-2023-31606

Package Information:
https://launchpad.net/ubuntu/+source/ruby-redcloth/4.3.2-4ubuntu0.23.04.1
https://launchpad.net/ubuntu/+source/ruby-redcloth/4.3.2-4ubuntu0.22.04.1
https://launchpad.net/ubuntu/+source/ruby-redcloth/4.3.2-3+deb10u1build0.20.04.1