CVE-2024-25979: Moodle Information Disclosure Vulnerability

CVE-2024-25979 Overview

CVE-2024-25979 affects the Moodle learning management system. The forum search feature accepts URL parameters without restricting them to an allowed list. This permissive parameter handling can lead to unintended behavior when attackers supply unexpected inputs through the search endpoint.

The weakness is categorized under [CWE-233] (Improper Handling of Parameters) and affects Moodle installations alongside the Fedora 38 distribution package. The issue requires no authentication and is remotely reachable over the network.

Critical Impact
Attackers can submit arbitrary URL parameters to the forum search endpoint, bypassing the intended parameter allowlist and potentially influencing search behavior or exposing information through unexpected query handling.

Affected Products

Moodle (multiple versions prior to the MDL-69774 fix)
Fedora Project Fedora 38
Moodle forum module (mod/forum)

Discovery Timeline

2024-02-19 - CVE-2024-25979 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-25979

Vulnerability Analysis

The Moodle forum search accepts arbitrary URL parameters rather than enforcing a strict allowlist. When a user submits a search request through the forum module, the handler processes query string parameters without validating them against a defined set of permitted keys.

This improper handling of parameters [CWE-233] creates an input validation gap. The impact is bounded in scope: the vulnerability affects integrity through unexpected search behavior, but does not directly expose confidential data or disrupt availability.

Root Cause

The root cause is missing parameter filtering in the forum search request pipeline. The code accepts any URL parameter supplied by the client and passes it into downstream processing. Without an allowlist, unexpected parameters influence search logic or state in ways the developers did not intend.

The Moodle commit MDL-69774 resolves the issue by restricting accepted parameters to those explicitly permitted by the search specification.

Attack Vector

Exploitation requires only a network request to a vulnerable Moodle forum search endpoint. No authentication or user interaction is required. An attacker crafts a URL containing additional or unexpected parameters and submits it to the forum search handler.

The vulnerability does not provide code execution or direct data exfiltration. Impact is limited to unintended search behavior resulting from parameter smuggling.

// No verified exploit code is publicly available for CVE-2024-25979.
// See Moodle advisory MDL-69774 and the Moodle discussion forum
// for technical details on the fix.

Detection Methods for CVE-2024-25979

Indicators of Compromise

Unusual query strings on mod/forum/search.php containing parameters outside the documented set
Repeated search requests from a single source enumerating parameter names
Web server logs showing forum search URLs with uncommon or malformed parameter keys

Detection Strategies

Review web access logs for requests to /mod/forum/search.php and compare parameters against the allowlist enforced by MDL-69774
Alert on anonymous (unauthenticated) requests to forum search endpoints that include non-standard parameters
Correlate repeated search requests from the same IP that iterate parameter names, indicating enumeration

Monitoring Recommendations

Enable verbose logging on the Moodle application tier for forum module requests
Forward web server and application logs to a centralized analytics platform for query pattern analysis
Monitor for anomalous spikes in forum search traffic that may indicate parameter fuzzing

How to Mitigate CVE-2024-25979

Immediate Actions Required

Upgrade Moodle to a version that includes the MDL-69774 fix as published in the Moodle Commit MDL-69774
For Fedora 38 deployments, apply the Moodle package update referenced in the Fedora Package Announcement
Audit forum search access logs for evidence of parameter enumeration since the vulnerability was disclosed

Patch Information

Moodle addressed the issue in commit MDL-69774, which restricts URL parameters accepted by forum search to the allowed set. Red Hat tracked the issue in Red Hat Bug Report #2264095, and the Fedora Project shipped an updated package for Fedora 38. Administrators should consult the Moodle Discussion Forum Post for release details.

Workarounds

Place a web application firewall (WAF) rule in front of Moodle that strips unexpected query parameters from requests to /mod/forum/search.php
Restrict unauthenticated access to the forum search endpoint via reverse proxy rules until patching is complete
Disable the forum search feature at the Moodle configuration level if operationally acceptable

bash

# Example nginx rule limiting forum search parameters to the allowed set
location = /mod/forum/search.php {
    if ($arg_unexpected != "") { return 400; }
    proxy_pass http://moodle_backend;
}