CVE-2025-7259 Overview
CVE-2025-7259 is a denial-of-service vulnerability in MongoDB Server version 8.1.0. An authenticated user can submit queries containing duplicate _id fields, triggering unexpected server behavior that may crash the process. The flaw is classified under [CWE-843] (Type Confusion) and requires valid credentials for exploitation. Successful exploitation disrupts database availability for all connected applications and users. The issue is tracked by MongoDB as SERVER-102693 and affects only the 8.1.0 release of MongoDB Server.
Critical Impact
An authenticated attacker can crash MongoDB Server 8.1.0 by issuing crafted queries with duplicate _id fields, causing full loss of database availability.
Affected Products
- MongoDB Server 8.1.0
Discovery Timeline
- 2025-07-07 - CVE-2025-7259 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-7259
Vulnerability Analysis
The vulnerability resides in MongoDB Server's query processing logic when a query document contains multiple _id fields. Rather than rejecting the malformed input or handling it deterministically, the server enters an unexpected state that can terminate the process. The impact is limited to availability; no data confidentiality or integrity impact has been reported. Because MongoDB frequently serves as a backend for web applications and microservices, an unexpected crash cascades into application-level outages.
Root Cause
The defect is categorized as [CWE-843], indicating type confusion or improper handling of a resource of an incompatible type. MongoDB's query planner does not consistently validate BSON documents where the reserved _id field appears more than once. This ambiguity leads the server down an unintended code path that can terminate execution. The regression is confined to the 8.1.0 development release line.
Attack Vector
Exploitation requires an authenticated session with permission to issue queries against a target collection. The attacker crafts a query document containing two or more _id fields and submits it through any standard MongoDB driver or the mongo shell. No elevated privileges, user interaction, or network positioning beyond normal client access are needed. Because the attack surface is any authorized query endpoint, insider threats and compromised application service accounts are the primary risk vectors.
No verified proof-of-concept code is publicly available. For technical details, refer to the MongoDB SERVER-102693 Issue Tracker.
Detection Methods for CVE-2025-7259
Indicators of Compromise
- Unexpected mongod process termination or restart events on hosts running MongoDB Server 8.1.0.
- Query log entries containing BSON documents with more than one _id field.
- Client-side connection reset errors clustered around a specific query pattern.
Detection Strategies
- Enable MongoDB profiling and audit logging to capture full query documents submitted by authenticated users.
- Parse query logs for BSON documents that include duplicate _id keys and alert on any occurrence.
- Correlate mongod crash events with preceding query patterns to identify probing activity.
Monitoring Recommendations
- Monitor MongoDB server uptime, restart counters, and process exit codes through your observability stack.
- Track authenticated query volume per user account and alert on anomalous spikes from application service accounts.
- Forward MongoDB audit logs to a centralized SIEM for retention and correlation with authentication events.
How to Mitigate CVE-2025-7259
Immediate Actions Required
- Inventory all MongoDB deployments and identify any instances running version 8.1.0.
- Upgrade affected servers to a fixed MongoDB Server release as published by MongoDB.
- Review role assignments and remove query privileges from accounts that do not require them.
- Rotate credentials for any application service account with broad query permissions.
Patch Information
MongoDB has tracked the fix under issue SERVER-102693. Refer to the MongoDB SERVER-102693 Issue Tracker for the authoritative list of patched versions and upgrade guidance. Apply the vendor-supplied update to any MongoDB Server 8.1.0 instance in production, staging, or development environments.
Workarounds
- Restrict direct query access to trusted application accounts and administrative users only.
- Add server-side input validation in application middleware to reject BSON documents containing duplicate _id fields before they reach mongod.
- Deploy network segmentation so that MongoDB endpoints are not reachable from untrusted client networks.
# Verify installed MongoDB Server version
mongod --version
# Example role hardening: grant read-only access instead of broad query privileges
mongosh --eval 'db.getSiblingDB("admin").grantRolesToUser("appUser", [{ role: "read", db: "appdb" }])'
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
