CVE-2025-53021: Medium severity Moodle Moodle vulnerability
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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-53021?
CVE-2025-53021 is considered a high-severity vulnerability due to its potential to allow session hijacking.
How do I fix CVE-2025-53021?
To fix CVE-2025-53021, upgrade Moodle to version 4.0.0 or later.
What versions of Moodle are affected by CVE-2025-53021?
CVE-2025-53021 affects Moodle versions from 3.0 through 3.11.18.
Can unauthenticated attackers exploit CVE-2025-53021?
Yes, unauthenticated attackers can exploit CVE-2025-53021 to hijack user sessions.
What can attackers do using CVE-2025-53021?
Attackers can hijack legitimate user sessions by misusing the sesskey parameter during the OAuth2 login flow.