CVE-2026-30884

CRITICAL 9.6

mdjnelson/moodle-mod_customcert Vulnerable to Authorization Bypass Through User-Controlled Key

CVSS Score

9.6

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-639
Vendor	mdjnelson
Product	moodle-mod_customcert
Published	Mar 18, 2026
Last Updated	Mar 18, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

mdjnelson / moodle-mod_customcert

< 4.4.9 >= 5.0.0, < 5.0.3

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/mdjnelson/moodle-mod_customcert/security/advisories/GHSA-8pjr-j7r4-ccjx github.com: https://github.com/mdjnelson/moodle-mod_customcert/commit/a1494a80fb953f187f7888a7394cbf9d13c28468 github.com: https://github.com/mdjnelson/moodle-mod_customcert/commit/ddc8f01f1e19fb61202f6013a38ef757486d3ba0