CVE-2025-32045: Moodle Auth Bypass Vulnerability

CVE-2025-32045 Overview

A flaw has been identified in Moodle where insufficient capability checks in certain grade reports allowed users without the necessary permissions to access hidden grades. This Missing Authorization vulnerability (CWE-862) enables unauthorized users to bypass access controls and view grade information that should be restricted from their view.

The vulnerability affects Moodle's grade reporting functionality, where proper authorization checks were not consistently enforced. This allows users with lower privilege levels to access sensitive academic information that educators or administrators had intentionally hidden from view.

Critical Impact

Unauthorized users can access hidden grade information in Moodle learning management systems, potentially exposing confidential academic data and violating student privacy policies.

Affected Products

• Moodle LMS (multiple versions affected)
• Moodle grade reporting modules
• Moodle capability/permission system

Discovery Timeline

• April 25, 2025 - CVE-2025-32045 published to NVD
• June 24, 2025 - Last updated in NVD database

Technical Details for CVE-2025-32045

Vulnerability Analysis

This vulnerability stems from a Missing Authorization weakness (CWE-862) in Moodle's grade reporting functionality. The flaw exists because certain grade report views fail to properly verify whether the requesting user possesses the appropriate capabilities to access hidden grade data.

In Moodle's permission model, instructors can hide grades from students for various pedagogical reasons—such as during grading periods or when preparing assessments. The vulnerability bypasses these intentional access restrictions, allowing users to retrieve grade information that should not be visible to them based on their assigned role and capabilities.

The network-accessible nature of this vulnerability means it can be exploited remotely without requiring any prior authentication in certain configurations, though the impact is limited to information disclosure of grade data.

Root Cause

The root cause of this vulnerability is insufficient capability checks within Moodle's grade report handling code. Specifically, the affected grade report modules do not properly validate the moodle/grade:viewhidden capability or equivalent permission checks before rendering hidden grade data to users.

When a user requests a grade report, the system fails to verify whether the user's assigned role includes permissions to view grades that have been marked as hidden. This oversight allows the hidden grade data to be included in responses to users who should not have access to this information.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no user interaction and no special privileges to exploit. An attacker can exploit this vulnerability by:

1. Authenticating to a vulnerable Moodle instance with any valid user account (or potentially without authentication in misconfigured instances)
2. Navigating to or directly requesting grade report endpoints
3. Viewing grade information that has been configured as hidden by course instructors

The vulnerability requires the attacker to have network access to the Moodle instance. The exploitation does not require complex techniques—simply accessing the grade report functionality through normal navigation paths may expose the hidden data. For detailed technical information, refer to the Red Hat CVE-2025-32045 Advisory and the Red Hat Bugzilla Report #2356835.

Detection Methods for CVE-2025-32045

Indicators of Compromise

• Unusual access patterns to grade report URLs from users with student or limited roles
• Log entries showing grade report access from users who should not have permission to view hidden grades
• Audit trail anomalies where users access grades outside their enrolled courses or sections
• Unexpected database queries to grade tables from non-administrative sessions

Detection Strategies

• Monitor Moodle access logs for repeated requests to grade report endpoints from non-instructor accounts
• Implement alerting on grade report access patterns that deviate from normal user behavior
• Review role assignments and capability overrides to identify potential privilege misconfigurations
• Enable and review Moodle's built-in event logging for grade viewing activities

Monitoring Recommendations

• Enable comprehensive logging for all grade-related activities in Moodle's event monitoring system
• Configure SIEM rules to detect access to grade endpoints from unexpected user roles
• Regularly audit user permissions and role assignments within Moodle courses
• Implement network-level monitoring for unusual traffic patterns to Moodle grade report URLs

How to Mitigate CVE-2025-32045

Immediate Actions Required

• Identify all Moodle instances in your environment and determine their version numbers
• Review Moodle security advisories and apply available patches immediately
• Audit current role definitions and capability assignments related to grade viewing
• Consider temporarily restricting access to grade reports until patches are applied

Patch Information

Organizations running affected versions of Moodle should update to the latest patched version as soon as possible. Consult the official Moodle security announcements and the Red Hat CVE-2025-32045 Advisory for specific version information and patch availability.

Administrators should follow Moodle's standard upgrade procedures, ensuring database backups are completed before applying updates. After patching, verify that capability checks are functioning correctly by testing grade visibility with various user roles.

Workarounds

• Temporarily disable or restrict access to affected grade report views until patches can be applied
• Review and tighten role definitions to minimize users with any grade viewing capabilities
• Implement additional access controls at the web server or reverse proxy level to limit grade report access
• Consider using Moodle's capability override feature to explicitly deny hidden grade viewing for all non-administrative roles

# Configuration example
# Review Moodle role capabilities via CLI (example for capability audit)
php admin/cli/cfg.php --name=debugdisplay --set=1

# Check current Moodle version
php admin/cli/upgrade.php --non-interactive --version-only

# Perform Moodle upgrade after downloading patched version
php admin/cli/upgrade.php --non-interactive