CVE-2025-67847: Moodle Restore Interface RCE Vulnerability

CVE-2025-67847 Overview

A critical code injection vulnerability has been identified in Moodle's restore interface. An authenticated attacker with access to the restore functionality can trigger server-side execution of arbitrary code due to insufficient validation of restore input data. This flaw allows malicious input to be unintentionally interpreted by core restore routines, potentially leading to a full compromise of the Moodle application, including unauthorized access to sensitive data, modification of educational content, and complete server takeover.

Critical Impact

Successful exploitation could result in complete compromise of the Moodle application, enabling attackers to execute arbitrary code on the server, access sensitive user data, and potentially pivot to other systems in the network.

Affected Products

• Moodle (specific versions not disclosed in advisory)

Discovery Timeline

• 2026-01-23 - CVE-2025-67847 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2025-67847

Vulnerability Analysis

This vulnerability is classified as CWE-94 (Improper Control of Generation of Code, also known as Code Injection). The flaw exists within Moodle's backup and restore functionality, which is designed to allow administrators and instructors to create and restore course backups. The restore interface fails to properly validate user-supplied input before processing it through the core restore routines.

When a backup file is restored, the system parses and processes various metadata and content elements. Due to insufficient input validation, an attacker can craft a malicious backup file containing code constructs that, when processed by the restore routines, are interpreted and executed on the server rather than being treated as data. This represents a classic code injection scenario where the boundary between code and data is not properly enforced.

The network-accessible nature of this vulnerability, combined with the low attack complexity and potential for complete system compromise, makes this a significant security concern for organizations running Moodle installations.

Root Cause

The root cause of this vulnerability lies in the insufficient validation of input data during the restore process. The core restore routines fail to properly sanitize or validate content from backup files before processing, allowing specially crafted input to be interpreted as executable code. This violates the principle of treating all external input as untrusted and demonstrates a failure to implement proper input validation at the security boundary where backup data enters the system.

Attack Vector

The attack requires an authenticated user with access to Moodle's restore interface—typically administrators, course managers, or instructors with backup/restore permissions. The attacker crafts a malicious backup file containing carefully constructed payloads within the backup structure. When this file is uploaded and processed through the restore interface, the insufficient validation allows the malicious payload to be executed server-side.

The attack follows this general pattern:

1. The attacker obtains or creates credentials with restore permissions
2. A malicious backup file is crafted containing code injection payloads
3. The attacker initiates a restore operation using the malicious file
4. The restore routines process the file without adequate validation
5. The injected code is executed with the privileges of the web server process

Detection Methods for CVE-2025-67847

Indicators of Compromise

• Unusual file creation or modification in Moodle's data directories following restore operations
• Unexpected outbound network connections from the Moodle server
• Suspicious processes spawned by the web server process (e.g., php, apache, or nginx)
• Anomalous backup files in upload or temporary directories with non-standard content structures

Detection Strategies

• Implement web application firewall (WAF) rules to inspect uploaded backup files for suspicious patterns
• Enable and monitor PHP error logs for code execution errors or warnings during restore operations
• Deploy file integrity monitoring on Moodle installation directories to detect unauthorized modifications
• Configure SIEM rules to correlate restore operations with subsequent suspicious system activity

Monitoring Recommendations

• Enable comprehensive logging for all backup and restore operations in Moodle
• Monitor system calls and process creation events on the Moodle server for anomalies
• Implement network monitoring to detect unexpected outbound connections from the web server
• Review restore activity logs regularly for operations performed by users who don't typically use this functionality

How to Mitigate CVE-2025-67847

Immediate Actions Required

• Restrict restore permissions to only essential administrative personnel until patches are applied
• Implement network segmentation to limit the blast radius of potential compromise
• Enable enhanced logging and monitoring for restore operations
• Review recent restore operations for any suspicious activity

Patch Information

Refer to the Red Hat CVE-2025-67847 Advisory for specific patch information and updates from Moodle. Organizations should apply vendor-provided security patches as soon as they become available. Monitor the official Moodle security announcements for patched versions and upgrade guidance.

Workarounds

• Temporarily disable the restore functionality if not operationally required
• Implement strict access controls limiting restore permissions to highly trusted administrators only
• Deploy web application firewall rules to inspect and filter backup file uploads
• Run Moodle in an isolated environment with restricted network access and system permissions