MongoDB Mongos Freeze: Unpacking CVE-2025-6714's Load Balancer DoS Vulnerability
MongoDB sharded clusters are the backbone of many enterprise applications, ensuring scalability and high availability. However, a newly discovered vulnerability, CVE-2025-6714, threatens to disrupt these critical systems by causing the mongos component to become unresponsive when configured with load balancers like HAProxy.
Technical Information
The root cause of CVE-2025-6714 is the incorrect handling of incomplete data packets by MongoDB's mongos component. Specifically, when mongos is deployed behind a load balancer, malformed or partial data packets can trigger an infinite resource exhaustion loop. This loop consumes available worker threads, causing mongos to freeze and reject new connection attempts.
This vulnerability is particularly severe in environments where load balancers misroute cursor and transaction requests, splitting them across multiple mongos nodes. Such misrouting exacerbates the issue, as cursor contexts are node-specific, leading to further instability and potential downtime.
Attack Vectors
Attackers can exploit this vulnerability remotely and without authentication by sending specifically crafted incomplete data packets through the load balancer to the mongos component. This exploitation scenario is particularly concerning for public-facing MongoDB deployments.
Affected Systems and Versions
The vulnerability specifically affects MongoDB Server in sharded cluster configurations using load balancers such as HAProxy. The affected version ranges are:
- MongoDB Server v6.0 prior to 6.0.23
- MongoDB Server v7.0 prior to 7.0.20
- MongoDB Server v8.0 prior to 8.0.9
Clusters not using load balancers or standalone MongoDB deployments are not affected by this vulnerability.
Vendor Security History
MongoDB Inc. has a strong track record of swiftly addressing security vulnerabilities. Historically, the vendor has promptly released patches for critical vulnerabilities, including similar issues related to load balancer integration. MongoDB's proactive approach to security updates and detailed security bulletins underscores their commitment to maintaining robust security standards.
References
- NVD CVE-2025-6714
- MongoDB JIRA SERVER-106753
- MongoDB 6.0.23 Release Announcement
- MongoDB 7.0.20 Release Announcement
- MongoDB 8.0.9 Release Announcement
- Tencent Cloud Mongos Load Balancing
Security teams managing MongoDB deployments should prioritize addressing CVE-2025-6714 to ensure uninterrupted database availability and stability.
Source: This report was created using AI
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