CVE-2026-18711

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Memory Corruption in MongoDB Server Query Engine

Publication date: 2026-08-11

Last updated on: 2026-08-28

Assigner: MongoDB, Inc.

Description

An issue in MongoDB Server's query execution engine could allow an authenticated user with read and write privileges to cause an internal reference to be used after the underlying memory has been freed, when running certain queries against time-series collections. This could result in a server crash or disclosure of freed memory contents within query results.

CVSS Scores

EPSS Scores

Probability:
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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-2026-18711

EUVD

EUVD-2026-56884

Affected Vendors & Products

Vendor	Product	Version / Range
mongodb	mongodb_server	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This vulnerability in MongoDB Server's query execution engine allows an authenticated user with read and write privileges to cause an internal reference to be used after the underlying memory has been freed. This occurs when running certain queries against time-series collections and could lead to a server crash or exposure of freed memory contents in query results.

Detection Guidance

Detection requires monitoring for server crashes or unusual memory disclosure in query results when using time-series collections. MongoDB does not provide specific detection commands in the provided context.

Impact Analysis

An attacker could exploit this to crash the MongoDB server or leak sensitive data from freed memory. This may cause service disruption, unauthorized information exposure, or potential further attacks if combined with other exploits.

Compliance Impact

This vulnerability could lead to unauthorized data access or disclosure, violating GDPR's data protection principles or HIPAA's confidentiality requirements. Organizations may face compliance violations, fines, or reputational damage if exploited.

Mitigation Strategies

Upgrade MongoDB Server to the latest patched version immediately. Restrict authenticated users with read/write privileges to only necessary operations. Avoid running untrusted queries on time-series collections until patched.

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