Vulnerability Description
A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter. The sesskey can be obtained without authentication and reused within the OAuth2 login flow, resulting in the victim's session being linked to the attacker's. Successful exploitation results in full account takeover. According to the Moodle Releases page, "Bug fixes for security issues in 3.11.x ended 11 December 2023." NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Moodle | Moodle | >= 3.0.0, <= 3.11.18 |
Related Weaknesses (CWE)
References
- https://github.com/moodle/moodle/releases/tag/v3.11.18Product
- https://moodledev.io/general/releases#moodle-311Product
- https://rentry.co/moodle-oauth2-cveThird Party Advisory
FAQ
What is CVE-2025-53021?
CVE-2025-53021 is a vulnerability with a CVSS score of 4.2 (MEDIUM). A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter. The sesskey can be obtained without authentication an...
How severe is CVE-2025-53021?
CVE-2025-53021 has been rated MEDIUM with a CVSS base score of 4.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-53021?
Check the references section above for vendor advisories and patch information. Affected products include: Moodle Moodle.