Ubuntu Security Notices USN-8323-1 USN-8323-1: Postorius vulnerability Publication date 27 May 2026 Overview Postorius could be made to expose sensitive information over the network. Releases 26.04 LTS 25.10 24.04 LTS 22.04 LTS 20.04 LTS 18.04 LTS Open side navigation Close side navigation Packages Details Update instructions References Packages postorius - Django based management interface for Mailman Details It was discovered that Postorius did not properly escape HTML in message subjects when rendering the Held messages pop-up. An attacker could possibly use this issue to inject arbitrary HTML, resulting in exposure of sensitive information. It was discovered that Postorius did not properly escape HTML in message subjects when rendering the Held messages pop-up. An attacker could possibly use this issue to inject arbitrary HTML, resulting in exposure of sensitive information. Update instructions In general, a standard system update will make all the necessary changes. Learn more about how to get the fixes. The problem can be corrected by updating your system to the following package versions: Ubuntu Release Package Version 26.04 LTS resolute python3-django-postorius – 1.3.13-1ubuntu1.1~26.04.1 25.10 questing python3-django-postorius – 1.3.13-1ubuntu1.1~25.10.1 24.04 LTS noble python3-django-postorius – 1.3.10-1ubuntu0.1~esm1 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. 22.04 LTS jammy python3-django-postorius – 1.3.5-1ubuntu0.1~esm1 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. 20.04 LTS focal python3-django-postorius – 1.2.4-1ubuntu0.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. 18.04 LTS bionic python-django-postorius – 1.1.2-3ubuntu0.1+esm1 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. 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. Get Ubuntu Pro References CVE-2026-44742 CVE-2026-44742