CVE-2026-30884 mdjnelson/moodle-mod_customcert Vulnerable to Authorization Bypass Through User-Controlled Key
Teachers can read and modify certificate elements in unauthorized courses due to missing context verification in the Moodle custom certificate plugin.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-30884?
CVE-2026-30884 is a critical missing authorization vulnerability in mdjnelson moodle-mod_customcert, published on 18 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
mdjnelson/moodle-mod_customcert is a Moodle plugin for creating dynamically generated certificates with complete customization via the web browser. Prior to versions 4.4.9 and 5.0.3, a teacher who holds `mod/customcert:manage` in any single course can read and silently overwrite certificate elements belonging to any other course in the Moodle installation. The `core_get_fragment` callback `editelement` and the `mod_customcert_save_element` web service both fail to verify that the supplied `elementid` belongs to the authorized context, enabling cross-course information disclosure and data tampering. Versions 4.4.9 and 5.0.3 fix the issue.
Weakness: CWE-639
Which versions are affected by CVE-2026-30884?
How do I fix CVE-2026-30884?
No fix has been published for CVE-2026-30884 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-30884 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-30884 exists.
Sources
Also known as GHSA-8pjr-j7r4-ccjx.