Cross-course data disclosure and tampering via unchecked ownership
Published Mar 18, 2026 · Updated Mar 18, 2026
Authorization bypass in Custom certificate before 4.4.9 and 5.0.0 through 5.0.2 allows remote authenticated users to read and alter cross-course elements. The editelement fragment callback and save_element and get_element_html web services accept an elementid without checking its template or context ownership. A teacher with mod/customcert:manage in one course can enumerate sequential IDs to disclose configuration or silently overwrite elements in other courses.
Summary
What happened
Authorization bypass in Custom certificate before 4.4.9 and 5.0.0 through 5.0.2 allows remote authenticated users to read and alter cross-course elements. The editelement fragment callback and save_element and get_element_html web services accept an elementid without checking its template or context ownership. A teacher with mod/customcert:manage in one course can enumerate sequential IDs to disclose configuration or silently overwrite elements in other courses.
The record
- CVE
- CVE-2026-30884
- Published
- Mar 18, 2026
- Updated
- Mar 18, 2026
- Vendor
- Mark Nelson
- Product
- Custom certificate
- Classifications
- CWE-639, T1565.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 18, 2026CVE publishedPublication date reported by the CVE source.
- Mar 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 4.4.9
- Affected versionversion=>= 5.0.0, < 5.0.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-8pjr-j7r4-ccjx proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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