A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter. (CVE-2025-53021)
A session fixation vulnerability exists in Moodle versions 3.0.0 through before 4.1.10, allowing unauthenticated attackers to hijack user sessions via the sesskey parameter. The sesskey can be obtained without authentication and reused within the OAuth2 login flow, linking the victim's session to the attacker’s. Exploitation results in full account takeover. This vulnerability affects unsupported Moodle versions, as security fixes for 3.11.x ended on December 11, 2023. A patch is available for affected versions.
AI Analysis
Technical Summary
Moodle versions from 3.0.0 up to but not including 4.1.10 are vulnerable to a session fixation attack through the sesskey parameter. Attackers can obtain the sesskey without authentication and reuse it in the OAuth2 login flow, causing the victim's session to be associated with the attacker’s session. This leads to full account takeover. The vulnerability affects unsupported versions of Moodle, with security fixes for 3.11.x ending in December 2023. A patch is available to address this issue.
Potential Impact
Successful exploitation allows unauthenticated attackers to hijack user sessions and achieve full account takeover. This compromises user accounts and potentially sensitive data within the Moodle platform. The vulnerability specifically affects unsupported Moodle versions, which no longer receive security updates.
Mitigation Recommendations
A patch is available for this vulnerability. Users should upgrade to Moodle versions 4.1.10 or later, which include the fix. Since the affected versions are no longer supported, upgrading to a supported version is strongly recommended to mitigate this risk.
A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter. (CVE-2025-53021)
Description
A session fixation vulnerability exists in Moodle versions 3.0.0 through before 4.1.10, allowing unauthenticated attackers to hijack user sessions via the sesskey parameter. The sesskey can be obtained without authentication and reused within the OAuth2 login flow, linking the victim's session to the attacker’s. Exploitation results in full account takeover. This vulnerability affects unsupported Moodle versions, as security fixes for 3.11.x ended on December 11, 2023. A patch is available for affected versions.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Moodle versions from 3.0.0 up to but not including 4.1.10 are vulnerable to a session fixation attack through the sesskey parameter. Attackers can obtain the sesskey without authentication and reuse it in the OAuth2 login flow, causing the victim's session to be associated with the attacker’s session. This leads to full account takeover. The vulnerability affects unsupported versions of Moodle, with security fixes for 3.11.x ending in December 2023. A patch is available to address this issue.
Potential Impact
Successful exploitation allows unauthenticated attackers to hijack user sessions and achieve full account takeover. This compromises user accounts and potentially sensitive data within the Moodle platform. The vulnerability specifically affects unsupported Moodle versions, which no longer receive security updates.
Mitigation Recommendations
A patch is available for this vulnerability. Users should upgrade to Moodle versions 4.1.10 or later, which include the fix. Since the affected versions are no longer supported, upgrading to a supported version is strongly recommended to mitigate this risk.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- BIT-moodle-2025-53021
- Osv Schema Version
- 1.6.2
- Aliases
- ["CVE-2025-53021"]
- Ecosystems
- ["Bitnami"]
- Database Specific Severity
- Medium
Threat ID: 6aa0060bacd9273b49ab729d
Added to database: 09/08/2026, 12:56:43 UTC
Last enriched: 09/08/2026, 13:40:30 UTC
Last updated: 09/10/2026, 19:36:51 UTC
Views: 30
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