CVE-2026-18711 in Server
Summary
by MITRE • 08/11/2026
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.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability exists within the MongoDB Server query execution engine and represents a classic use-after-free condition that can be exploited by authenticated users possessing read and write privileges. The flaw specifically manifests when executing certain queries against time-series collections, which are designed to store temporal data with optimized storage and retrieval patterns. The underlying technical issue occurs when the server's query processor maintains internal references to memory locations that have already been freed during the query execution lifecycle. This memory management error creates a scenario where subsequent operations attempt to access deallocated memory regions, leading to unpredictable behavior including application crashes or information disclosure.
The operational impact of this vulnerability extends beyond simple service disruption as it can potentially expose sensitive data contained within freed memory segments. When the server processes queries against time-series collections, the query engine's handling of memory references becomes critical to system stability and data integrity. Attackers with read and write privileges can craft specific query patterns that trigger the use-after-free condition, potentially causing denial of service through server crashes or extracting confidential information from memory contents that might include database credentials, user data, or system configuration details. This vulnerability particularly affects MongoDB deployments using time-series collections which are commonly employed in monitoring and analytics applications where temporal data is frequently queried.
The root cause of this issue aligns with CWE-416, which describes the use of freed memory condition, and demonstrates how improper memory management can create security vulnerabilities even in well-established database systems. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1059.003 for command and scripting interpreter, as attackers might leverage such conditions to execute malicious queries that could further compromise the system. The authentication requirement reduces the attack surface but does not eliminate the risk since authorized users with read-write privileges can potentially exploit this condition without additional privileges. Organizations using MongoDB with time-series collections should prioritize patching this vulnerability as it represents a serious security concern that could be exploited to gain unauthorized access to sensitive information or disrupt database services.
Mitigation strategies include immediate deployment of vendor-provided security patches and updates to the MongoDB server software. System administrators should implement monitoring for unusual query patterns against time-series collections that might indicate exploitation attempts. Additionally, network segmentation and privilege minimization practices can help reduce the potential impact if an attacker gains access to a valid account with read-write permissions. Regular security assessments of database configurations and query execution patterns should be conducted to identify and remediate similar memory management issues before they can be exploited by threat actors. The vulnerability underscores the importance of rigorous memory management practices in server-side applications and highlights why regular security updates are critical for maintaining database system integrity and protecting against sophisticated attack vectors that target underlying software infrastructure.