CVE-2026-18697

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Denial of Service in MongoDB Server via Aggregation Command

Publication date: 2026-08-11

Last updated on: 2026-08-28

Assigner: MongoDB, Inc.

Description

An issue in MongoDB Server's aggregation framework could allow an unauthenticated party to cause a mongos (router) process to terminate unexpectedly by submitting a specially formed aggregation command. This could result in a denial of service, disrupting client connections routed through the affected mongos instance.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-11

Last Modified

2026-08-28

Generated

2026-09-01

AI Q&A

2026-08-12

EPSS Evaluated

2026-08-30

NVD

CVE-2026-18697

EUVD

EUVD-2026-56910

Affected Vendors & Products

Vendor	Product	Version / Range
mongodb	mongodb_server	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-617	The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Attack-Flow Graph

Executive Summary

This vulnerability is in MongoDB Server's aggregation framework. An unauthenticated attacker can send a specially crafted aggregation command to cause the mongos (router) process to crash unexpectedly. This leads to a denial of service, disrupting client connections that rely on the affected mongos instance.

Detection Guidance

This vulnerability can be detected by monitoring for unexpected termination of mongos processes. Check MongoDB logs for aggregation-related crashes or errors. Use system monitoring tools like 'ps' or 'systemctl' to verify mongos process status. No specific commands are provided in the context.

Impact Analysis

If exploited, this flaw could disrupt database operations by crashing the mongos process. This would interrupt client connections routed through that instance, potentially causing downtime or service unavailability for applications relying on MongoDB.

Compliance Impact

This vulnerability causes a denial of service by crashing the mongos process, disrupting client connections. While it does not directly impact data confidentiality or integrity, service disruptions could lead to compliance issues under GDPR (availability principle) or HIPAA (access controls and availability requirements).

Mitigation Strategies

Update MongoDB Server to the latest patched version immediately to address the aggregation framework issue. Monitor mongos processes for unexpected terminations and review logs for suspicious aggregation commands.

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