Vulnerability in Bludit software

CERT Polska has received a report about vulnerability in Bludit software and participated in coordination of its disclosure.

The vulnerabilityCVE-2026-4420: Bludit is vulnerable to Stored Cross-Site Scripting (XSS) in its page creating functionality. An authenticated attacker with page creation privileges (such as Author, Editor, or Administrator) can embed a malicious JavaScript payload in the tags field of a newly created article. This payload will be executed when a victim visits the URL of the uploaded resource. The uploaded resource itself is accessible without authentication. Critically, this vulnerability could be used to automatically create a new site administrator if the victim has enough privileges.

The vendor was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Only versions 3.17.2 and 3.18.0 were tested and confirmed as vulnerable, other versions were not tested and might also be vulnerable.

We thank Yassin Abdelrazek for the responsible vulnerability report.