CVE-2024-38276: Fedoraproject Fedora CSRF Vulnerability

CVE-2024-38276 Overview

CVE-2024-38276 is a Cross-Site Request Forgery (CSRF) vulnerability affecting Moodle, the open-source learning management system. Incorrect CSRF token validation in multiple Moodle endpoints exposes authenticated users to forged state-changing requests. An attacker can trick a logged-in user into executing unintended actions by directing them to a malicious page or link. The flaw is tracked under CWE-352 and impacts Moodle 4.4.0 and earlier maintained branches, with downstream impact on Fedora 39 and Fedora 40 distributions that ship the affected Moodle packages.

Critical Impact

Authenticated Moodle users visiting attacker-controlled content can trigger high-impact actions on the platform without their consent, leading to confidentiality, integrity, and availability loss.

Affected Products

• Moodle 4.4.0 and prior maintained versions
• Fedora 39
• Fedora 40

Discovery Timeline

• 2024-06-18 - CVE-2024-38276 published to NVD
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-38276

Vulnerability Analysis

The vulnerability stems from incorrect CSRF token verification across multiple request handlers in Moodle. CSRF tokens, known in Moodle as sesskey values, must be validated server-side before any state-changing operation executes. When validation is missing, performed incorrectly, or bypassable, a remote attacker can craft requests that ride on a victim's authenticated session.

User interaction is required for exploitation. The victim must visit attacker-controlled content while authenticated to a vulnerable Moodle instance. Because Moodle issues session cookies that the browser automatically attaches to outbound requests, the forged request executes with the victim's privileges.

The impact scope depends on the privilege level of the targeted user. Site administrators and teachers represent the highest-value targets because forged requests can modify course content, change configuration, or alter user data.

Root Cause

The root cause is improper enforcement of anti-CSRF controls [CWE-352] in multiple Moodle code paths. Specific endpoints either omitted the sesskey check or implemented it in a way that allowed bypass. Moodle resolved the issue by adding correct token validation across the affected request handlers, as referenced in the Moodle Security Discussion.

Attack Vector

Exploitation occurs over the network. An attacker hosts a malicious page containing crafted HTML or JavaScript that issues a request to the target Moodle endpoint. When an authenticated victim loads the page, the browser sends the request along with valid session cookies. The vulnerable endpoint accepts the request because token validation is missing or flawed and performs the requested action under the victim's identity.

The vulnerability mechanism is described in the Moodle Security Discussion. No public proof-of-concept code has been published for this CVE.

Detection Methods for CVE-2024-38276

Indicators of Compromise

• HTTP referrer headers in Moodle web logs pointing to external domains immediately preceding privileged state changes such as role assignments or configuration updates.
• Unexpected administrative actions, course modifications, or user permission changes recorded in the Moodle event log without corresponding interactive navigation.
• POST requests to Moodle endpoints lacking or carrying mismatched sesskey parameters in archived web server logs.

Detection Strategies

• Audit the Moodle event log (mdl_logstore_standard_log) for state-changing actions correlated with cross-origin referrers.
• Inspect web server access logs for clusters of POST requests originating from a single user session within a short window, particularly after the user followed an external link.
• Compare current Moodle administrative configuration against known-good baselines to detect unauthorized changes introduced via forged requests.

Monitoring Recommendations

• Forward Moodle application logs and reverse proxy access logs to a centralized SIEM for correlation against threat intelligence.
• Alert on referrer header anomalies on sensitive endpoints such as /admin/, /user/editadvanced.php, and /course/edit.php.
• Track privileged user sessions for activity patterns inconsistent with normal teaching or administration workflows.

How to Mitigate CVE-2024-38276

Immediate Actions Required

• Upgrade Moodle to the patched release identified in the Moodle Security Discussion for your maintained branch.
• On Fedora 39 and 40, apply the package updates referenced in the Fedora Package Announcement (F7AZYR7) and Fedora Package Announcement (GHTIX55).
• Force a session reset for administrative and privileged accounts to invalidate any in-flight forged requests.

Patch Information

Moodle released fixes that correct CSRF token verification in the affected handlers. Fedora project shipped updated moodle packages for Fedora 39 and Fedora 40 distributing the upstream patches. Administrators running self-hosted Moodle instances should follow the upstream guidance referenced in the Moodle security advisory and rebuild from the patched source or distribution package.

Workarounds

• Restrict Moodle administrative interfaces to trusted network segments or VPN-only access to reduce attacker reach to authenticated administrators.
• Educate privileged users to avoid clicking external links while logged into Moodle and to use a dedicated browser profile for administrative tasks.
• Configure the reverse proxy or web server to enforce SameSite=Strict on Moodle session cookies where compatible with deployment requirements.

# Example: enforce SameSite=Strict on Moodle session cookies via Apache
Header edit Set-Cookie ^(MoodleSession.*)$ "$1; SameSite=Strict; Secure"