CVE-2026-18692 in Server
Summary
by MITRE • 08/11/2026
An issue in MongoDB Server's handling of timeseries bucket lifecycle could allow an authenticated user with write privileges to cause an internal reference to be used after the underlying memory has been freed. Subsequent operations could then result in a server crash or, potentially, execution of unintended code.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability resides within MongoDB Server's implementation of timeseries data handling, specifically concerning how the system manages bucket lifecycle operations. The flaw manifests when an authenticated user possesses write privileges and manipulates timeseries data in a manner that triggers premature memory deallocation. The underlying technical issue stems from improper memory management where internal references to memory locations are maintained even after the associated memory has been freed, creating a classic use-after-free condition that represents a fundamental weakness in the software's resource handling mechanisms.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable remote code execution, making it particularly dangerous for systems where MongoDB serves as a critical data repository. When the server encounters subsequent operations that attempt to access the freed memory location through the stale reference, the behavior becomes unpredictable and can result in segmentation faults leading to server crashes or more severe outcomes including arbitrary code execution. This vulnerability directly aligns with CWE-416 which defines use-after-free conditions as a critical security weakness where software continues to use a pointer after it has been freed, creating opportunities for attackers to manipulate program flow.
The attack vector requires authentication and write privileges within the MongoDB environment, meaning that the threat actor must already have legitimate access to the database system. However, this limitation does not diminish the severity since authenticated attackers with write permissions can cause significant damage through privilege escalation techniques. The vulnerability is particularly concerning in environments where MongoDB operates with elevated privileges or where multiple applications share the same database instance, as it could potentially allow attackers to compromise other services running on the same host.
Mitigation strategies should focus on immediate patching of affected MongoDB versions and implementation of proper access controls to limit write privileges to only necessary users. Network segmentation and monitoring for unusual database operations can help detect potential exploitation attempts. Additionally, implementing memory safety checks and using tools like address sanitizers during development could prevent similar issues in future implementations. The vulnerability demonstrates the importance of proper resource management in database systems and aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, as attackers might leverage such memory corruption vulnerabilities to execute malicious code remotely through database interactions. Organizations should also consider implementing automated patch management processes to ensure timely updates of database software components that address known memory safety issues.