CVE-2025-3641 Overview
CVE-2025-3641 is a remote code execution vulnerability in the Moodle learning management system (LMS). The flaw resides in the Dropbox repository component and allows authenticated users with elevated roles to execute arbitrary code on the underlying server. By default, the affected functionality is available to users assigned teacher or manager roles on sites where the Dropbox repository is enabled. The vulnerability is classified under CWE-94: Improper Control of Generation of Code, commonly referred to as code injection. Moodle disclosed the issue through its community forum, and Red Hat assigned a high-severity rating.
Critical Impact
Authenticated teachers or managers can execute arbitrary code on Moodle servers where the Dropbox repository is enabled, leading to full compromise of confidentiality, integrity, and availability.
Affected Products
- Moodle LMS (versions with Dropbox repository functionality)
- Moodle deployments on Red Hat distributions referencing the same upstream code
- Any Moodle site administrator configuration where the Dropbox repository plugin is enabled
Discovery Timeline
- 2025-04-25 - CVE-2025-3641 published to NVD
- 2025-06-24 - Last updated in NVD database
Technical Details for CVE-2025-3641
Vulnerability Analysis
The vulnerability exists within the Moodle Dropbox repository plugin, a built-in module that allows users to import external files into Moodle activities. The plugin processes input that is later interpreted as code or passed to a function capable of evaluating code. An authenticated user with the teacher or manager role can craft input that triggers code execution on the Moodle server. The flaw maps to CWE-94 (Code Injection), indicating that the application generates or evaluates code from data without adequate validation or sanitization. Successful exploitation grants the attacker the privileges of the web server process running Moodle, enabling data theft, lateral movement, and persistence.
Root Cause
The root cause is improper neutralization of user-controlled input that is incorporated into a code execution path inside the Dropbox repository code. Moodle did not publish a public technical breakdown of the vulnerable function. Refer to the Moodle Forum Discussion and the Red Hat CVE Advisory for vendor-confirmed details.
Attack Vector
The attack is delivered over the network against the Moodle web interface. The attacker must authenticate and possess a teacher or manager role, or compromise an account already holding those privileges. No user interaction beyond the attacker's own session is required. Sites that have disabled the Dropbox repository at the admin level are not exposed. The EPSS score of 0.574% reflects relatively low observed exploitation activity at the time of publication, though privileged role requirements may suppress mass scanning.
No verified public proof-of-concept code is available. The exploitation mechanism in prose: an authenticated teacher or manager submits crafted parameters through the Dropbox repository workflow, and the server evaluates that input as executable code within the PHP runtime context of Moodle.
Detection Methods for CVE-2025-3641
Indicators of Compromise
- Unexpected PHP processes spawned by the Moodle web server user, particularly those invoking shell utilities such as sh, bash, curl, or wget.
- New or modified files under the Moodle moodledata directory, repository/dropbox/ paths, or web-accessible directories.
- Outbound connections from the Moodle host to unfamiliar IP addresses or Dropbox API endpoints initiated outside of normal usage windows.
- Moodle log entries showing repeated Dropbox repository operations from a single teacher or manager account.
Detection Strategies
- Monitor Moodle application logs (config.php log targets and the mdl_logstore_standard_log table) for repeated repository_dropbox events tied to a single user.
- Deploy endpoint detection on the Moodle host to flag child processes spawned by the PHP-FPM or Apache worker that are inconsistent with normal Moodle behavior.
- Inspect web server access logs for POST requests to /repository/repository_ajax.php and Dropbox-related endpoints from teacher or manager sessions.
Monitoring Recommendations
- Enable file integrity monitoring on repository/dropbox/ and the Moodle plugin directories.
- Forward Moodle, web server, and host process logs to a centralized SIEM and correlate authentication events with file write and process execution telemetry.
- Alert on privilege role assignments that grant the teacher or manager role outside of approved provisioning workflows.
How to Mitigate CVE-2025-3641
Immediate Actions Required
- Upgrade Moodle to the patched release identified in the Moodle Forum Discussion for CVE-2025-3641.
- Audit accounts holding the teacher and manager roles and revoke access where it is not required.
- Rotate credentials and API tokens for any account that interacted with the Dropbox repository before patching.
Patch Information
Moodle released a fix referenced in the official Moodle Forum Discussion for CVE-2025-3641. Red Hat tracks the issue in Bug Report #2359735 and the Red Hat CVE Advisory. Administrators should apply the upstream patch corresponding to their Moodle major version branch.
Workarounds
- Disable the Dropbox repository under Site administration > Plugins > Repositories > Manage repositories until the patch is applied.
- Restrict the teacher and manager roles to vetted users and enforce multi-factor authentication on those accounts.
- Place the Moodle application behind a web application firewall and rate-limit requests to /repository/repository_ajax.php.
# Disable the Dropbox repository via Moodle CLI
php admin/cli/cfg.php --component=repository_dropbox --name=enabled --set=0
# Verify the setting
php admin/cli/cfg.php --component=repository_dropbox --name=enabled
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
