CVE-2025-14911: MongoDB GridFS Buffer Overflow Flaw

CVE-2025-14911 Overview

CVE-2025-14911 is an input validation vulnerability affecting MongoDB's GridFS implementation. User-controlled chunkSize metadata from MongoDB lacks appropriate validation, allowing malformed GridFS metadata to overflow the bounding container. This vulnerability enables attackers with low privileges to cause a denial of service condition through network-accessible attack vectors.

Critical Impact

Authenticated attackers can exploit insufficient validation of GridFS chunkSize metadata to cause container overflow, resulting in high availability impact and potential service disruption.

Affected Products

• MongoDB C Driver (affected versions not specified)
• Applications using MongoDB GridFS with user-controlled metadata
• Systems processing untrusted GridFS file uploads

Discovery Timeline

• 2026-01-27 - CVE-2025-14911 published to NVD
• 2026-01-29 - Last updated in NVD database

Technical Details for CVE-2025-14911

Vulnerability Analysis

This vulnerability stems from inadequate validation of the chunkSize metadata field within MongoDB's GridFS file storage system. GridFS is MongoDB's specification for storing and retrieving large files by dividing them into smaller chunks. The chunkSize metadata field determines the size of these chunks, and when this value is user-controllable without proper bounds checking, it can lead to container overflow conditions.

The attack requires network access and low-level privileges, meaning an authenticated user with minimal permissions can exploit this flaw. The primary impact is on system availability, as exploiting this vulnerability can cause service disruption without compromising data confidentiality or integrity.

Root Cause

The root cause is improper input validation of the chunkSize metadata parameter in GridFS operations. When processing file uploads or metadata modifications, the system fails to adequately validate that user-supplied chunkSize values fall within acceptable bounds. This allows malformed metadata to be processed, leading to overflow conditions within the bounding container that manages chunk allocation.

Attack Vector

The attack is conducted over the network by an authenticated user with low privileges. The attacker crafts a malicious GridFS request containing an oversized or malformed chunkSize value in the metadata. When the MongoDB driver processes this metadata without proper validation, it triggers an overflow condition in the container responsible for managing chunk boundaries. No user interaction is required for exploitation.

The vulnerability mechanism involves sending crafted GridFS metadata with malicious chunkSize values. When the MongoDB C Driver processes these values without adequate bounds validation, the bounding container overflows, leading to denial of service. For detailed technical information, refer to the MongoDB Jira Ticket CDRIVER-6125.

Detection Methods for CVE-2025-14911

Indicators of Compromise

• Unusual GridFS operations with abnormally large or negative chunkSize values in MongoDB logs
• Unexpected service crashes or restarts in MongoDB-connected applications
• Memory allocation errors or container overflow messages in application logs
• Anomalous patterns in GridFS metadata modifications from specific users or sessions

Detection Strategies

• Monitor MongoDB audit logs for GridFS operations with suspicious chunkSize metadata values outside normal ranges
• Implement application-layer logging to track all GridFS metadata modifications and flag outliers
• Deploy SentinelOne Singularity Platform to detect anomalous process behavior associated with memory overflow conditions
• Configure alerting for MongoDB driver errors related to chunk size validation or memory allocation failures

Monitoring Recommendations

• Enable MongoDB profiling to capture slow or problematic GridFS operations for forensic analysis
• Implement network monitoring to detect patterns of repeated malformed GridFS requests from single sources
• Configure application performance monitoring (APM) to track service availability and detect DoS conditions early
• Review MongoDB C Driver logs for CDRIVER-6125 related warnings or errors

How to Mitigate CVE-2025-14911

Immediate Actions Required

• Review and audit all GridFS implementations in your environment for exposure to user-controlled metadata
• Implement application-level validation of chunkSize values before passing to MongoDB operations
• Restrict GridFS upload capabilities to trusted users until patches are applied
• Monitor for exploitation attempts using the detection strategies outlined above

Patch Information

Refer to the MongoDB Jira Ticket CDRIVER-6125 for official patch status and updates from MongoDB. Organizations should monitor this ticket for release announcements and apply patches as soon as they become available.

Workarounds

• Implement strict input validation at the application layer to enforce acceptable chunkSize bounds (typically 255KB to 16MB)
• Use network segmentation to limit access to MongoDB instances from untrusted networks
• Apply principle of least privilege to restrict which users can perform GridFS operations
• Consider disabling GridFS functionality temporarily if not critical to operations until patches are available

# Configuration example - Application-level chunkSize validation
# Add validation before GridFS operations to ensure chunkSize is within bounds
# Minimum: 1 byte, Maximum: 16793600 bytes (default GridFS limit)
# Example validation logic in application code:
# if (chunkSize < 1 || chunkSize > 16793600) {
#     reject_request("Invalid chunkSize value");
# }