Moodle Brickfield Tool CSRF Vulnerability (CVE-2025-3638): Analysis and Mitigation

A high-severity Cross-Site Request Forgery (CSRF) vulnerability has been identified in Moodle’s Brickfield tool, tracked as CVE-2025-3638. The flaw, which affects multiple Moodle versions, allows attackers to execute unauthorized actions by bypassing CSRF protections. With a CVSS score of 8.8 (High), this vulnerability poses risks to data integrity and system security in educational platforms using Moodle.

**TL;DR Summary**
– **Vulnerability**: CSRF in Moodle Brickfield tool due to missing token validation
– **CVSS**: 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
– **Affected Versions**: Moodle 4.1.0–4.1.17, 4.3.0–4.3.11, 4.4.0–4.4.7, 4.5.0–4.5.3
– **Patched Versions**: 4.1.18, 4.3.12, 4.4.8, 4.5.4
– **Exploitability**: Requires user interaction; no known public exploits
– **Mitigation**: Immediate upgrade recommended

Technical Analysis

The vulnerability stems from the absence of CSRF token validation in the Brickfield tool’s analysis request function. Attackers can craft malicious requests that, when executed by an authenticated user, perform unintended actions such as data modification or deletion. The flaw was reported by researcher Vincent Schneider on April 22, 2025, and publicly disclosed via NVD on April 25¹.

Moodle’s Brickfield tool, designed for accessibility analysis, processes user-submitted content. The CSRF gap enables attackers to manipulate this workflow. For example, a forged request could alter course accessibility settings or delete analysis reports without the victim’s knowledge. The attack requires the victim to be logged into Moodle and tricked into visiting a malicious page.

Affected Systems and Patch Status

The vulnerability impacts Moodle installations across four major release branches. The following table details affected and patched versions:

Branch	Affected Versions	Patched Version
4.1.x	4.1.0–4.1.17	4.1.18
4.3.x	4.3.0–4.3.11	4.3.12
4.4.x	4.4.0–4.4.7	4.4.8
4.5.x	4.5.0–4.5.3	4.5.4

Patches are available through Moodle’s official channels³. Administrators should prioritize updates, as the vulnerability is part of a broader security release addressing 16 Moodle flaws.

Detection and Mitigation

Organizations running Moodle should check their version against the affected list. The following command can help identify the installed version:

# From Moodle's admin panel:
Site administration → Notifications → Check for updates

For environments where immediate patching isn’t feasible, temporary mitigations include:
– Restricting access to the Brickfield tool via .htaccess or similar controls
– Implementing web application firewalls (WAFs) with CSRF protection rules
– Educating users about phishing risks that could lead to CSRF exploitation

Security Implications

This vulnerability highlights the importance of consistent CSRF protections across all state-changing actions in web applications. While the EPSS score suggests low immediate exploitation risk (0.05%), the high CVSS score indicates significant potential impact if exploited. Security teams should monitor for:
– Unusual Brickfield tool activity in logs
– Unexpected changes to accessibility settings
– Phishing campaigns targeting Moodle users

The flaw is classified under CWE-352 (Missing CSRF Token)⁴, a common weakness in web applications. Moodle’s prompt patch release demonstrates effective vulnerability management, though administrators must act swiftly to apply updates.

Conclusion

CVE-2025-3638 presents a concrete risk to Moodle deployments, particularly in educational institutions relying on the Brickfield tool. While exploitation requires user interaction, the high impact warrants urgent attention. Organizations should:
1. Upgrade to patched versions immediately
2. Audit logs for signs of attempted exploitation
3. Review CSRF protections across all custom Moodle plugins

This incident reinforces the need for comprehensive input validation and security testing in e-learning platforms. Future Moodle updates should be monitored closely, as this vulnerability was part of a larger security update addressing multiple issues.