CVE-2024-8654: MongoDB Use-After-Free Vulnerability

CVE-2024-8654 Overview

CVE-2024-8654 is an Uninitialized Memory Use vulnerability in MongoDB Server that allows access to non-initialized regions of memory when zero arguments are passed to an internal aggregation stage. This memory safety issue can lead to unexpected behavior and potentially allow attackers to compromise the confidentiality, integrity, and availability of affected MongoDB deployments.

Critical Impact

Network-accessible attackers without authentication can exploit this uninitialized memory vulnerability in MongoDB's aggregation pipeline, potentially leading to information disclosure, data corruption, or service disruption.

Affected Products

• MongoDB Server version 6.0.3
• MongoDB Server v6.0 series (prior to patch)
• NetApp products utilizing affected MongoDB versions (see NetApp Security Advisory)

Discovery Timeline

• 2024-09-10 - CVE-2024-8654 published to NVD
• 2025-09-22 - Last updated in NVD database

Technical Details for CVE-2024-8654

Vulnerability Analysis

This vulnerability falls under CWE-908 (Use of Uninitialized Resource), a memory safety issue where the MongoDB Server accesses memory that has not been properly initialized. The flaw exists within the internal aggregation stage processing logic, specifically when handling edge cases where zero arguments are provided to certain aggregation operations.

When an aggregation pipeline stage receives zero arguments, the server fails to properly initialize the memory region that would normally hold argument data. Subsequent operations then read from this uninitialized memory, leading to undefined behavior. This can manifest as information leakage (reading residual data from previous operations), unexpected query results, or application crashes.

The vulnerability is particularly concerning because it can be triggered remotely over the network without requiring authentication or user interaction. Attackers with network access to an exposed MongoDB instance could craft malicious aggregation queries designed to trigger this condition.

Root Cause

The root cause of CVE-2024-8654 is improper memory initialization in MongoDB's aggregation pipeline handling code. When processing aggregation stages, the server allocates memory to store argument data but fails to initialize this memory when the argument count is zero. This violates secure coding practices that require all memory to be initialized before use, regardless of expected content.

The specific issue occurs in the internal aggregation stage processing where boundary conditions for zero-argument invocations were not properly handled, leaving memory in an indeterminate state that could contain sensitive data from previous operations or arbitrary values.

Attack Vector

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

1. Establishing a connection to an exposed MongoDB Server instance
2. Constructing an aggregation query that triggers the vulnerable code path with zero arguments
3. Observing the resulting behavior which may expose uninitialized memory contents or cause service disruption

The vulnerability in the aggregation pipeline can be triggered through specially crafted queries that invoke internal aggregation stages with zero arguments. This causes the server to access uninitialized memory regions, potentially exposing sensitive information or causing denial of service. For technical implementation details, refer to the MongoDB Issue Tracking page.

Detection Methods for CVE-2024-8654

Indicators of Compromise

• Unusual aggregation queries with empty or zero argument stages in MongoDB logs
• Unexpected server crashes or restarts related to aggregation operations
• Anomalous query patterns targeting aggregation pipeline functionality
• Memory-related errors in MongoDB server logs

Detection Strategies

• Monitor MongoDB audit logs for aggregation queries with unusual argument patterns
• Implement network-level monitoring for connections to MongoDB ports from untrusted sources
• Deploy application-layer firewalls or proxies that can inspect MongoDB wire protocol traffic
• Enable MongoDB profiling to capture and analyze slow or suspicious aggregation operations

Monitoring Recommendations

• Configure MongoDB to log all aggregation pipeline operations for forensic analysis
• Set up alerts for MongoDB server crashes or unexpected restarts
• Monitor system memory utilization patterns for anomalies during aggregation operations
• Implement SIEM rules to detect potential exploitation attempts based on query patterns

How to Mitigate CVE-2024-8654

Immediate Actions Required

• Upgrade MongoDB Server to a patched version beyond 6.0.3
• Restrict network access to MongoDB instances using firewalls and network segmentation
• Enable MongoDB authentication if not already configured
• Review and audit aggregation pipeline usage in applications for unusual patterns

Patch Information

MongoDB has addressed this vulnerability in versions subsequent to 6.0.3. Organizations should upgrade to the latest stable release in the 6.0 series or migrate to a newer major version that includes the security fix. Detailed patch information is available through the MongoDB Issue Tracking system.

For environments using NetApp products with embedded MongoDB, consult the NetApp Security Advisory NTAP-20250516-0008 for specific guidance on affected products and remediation steps.

Workarounds

• Implement network-level access controls to limit MongoDB exposure to trusted networks only
• Use MongoDB's built-in authentication and authorization to restrict aggregation operations
• Deploy a reverse proxy or application gateway to filter potentially malicious aggregation queries
• Consider disabling or restricting access to aggregation pipeline functionality if not required

# Configuration example: Restrict MongoDB network binding
# In mongod.conf, limit binding to localhost or trusted interfaces
net:
  bindIp: 127.0.0.1
  port: 27017

# Enable authentication
security:
  authorization: enabled