CVE-2026-18700 in Server
Summary
by MITRE • 08/11/2026
An issue in MongoDB Server's geospatial validation could allow an authenticated user with write privileges to cause an internal reference to be used after the underlying memory has been freed, through concurrent operations against a collection using a certain type of validator. This could result in a server crash, leading to a denial of service.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical memory safety issue within MongoDB Server's geospatial validation mechanism that arises from improper handling of concurrent operations involving specific validator types. The flaw occurs when an authenticated user with write privileges manipulates collection data through geospatial validation rules, creating conditions where internal references become invalid before their associated memory is properly released. This memory management error manifests as a use-after-free condition that can be exploited to trigger server instability and ultimately cause denial of service attacks.
The technical root cause stems from inadequate synchronization mechanisms during concurrent write operations against collections that utilize geospatial validators. When multiple threads or processes attempt to modify geospatial data simultaneously, the validation system fails to properly manage reference counting or memory lifecycle management for internal data structures. This vulnerability specifically affects MongoDB Server implementations where geospatial indexing and validation are actively employed, creating a scenario where concurrent operations against collections with certain validator configurations can lead to memory corruption.
The operational impact of this vulnerability extends beyond simple service disruption as it represents a potential pathway for attackers to escalate privileges or cause persistent system instability. An authenticated attacker with write access can craft specific geospatial data modifications that, when processed concurrently, trigger the memory corruption leading to server crashes. This creates a denial of service condition that can be difficult to detect and mitigate since the vulnerability manifests only under specific concurrent operation patterns involving geospatial validation rules.
The vulnerability aligns with CWE-416, which addresses use-after-free conditions in software implementations, and demonstrates how improper memory management in database systems can create significant security risks. From an attack perspective, this issue maps to ATT&CK technique T1499.004 for network denial of service and potentially T1566.001 for initial access through privilege escalation scenarios. Organizations should implement immediate mitigations including restricting write privileges for geospatial operations, implementing proper concurrent access controls, and applying the latest MongoDB security patches to address the underlying memory management issues in the validation subsystem.
Defense-in-depth strategies should include monitoring for unusual concurrent write patterns against geospatial collections, implementing proper access controls limiting who can modify spatial data, and establishing robust intrusion detection systems that can identify potential exploitation attempts. The vulnerability highlights the importance of proper memory management in database engines and underscores the need for thorough testing of concurrent operation scenarios, particularly in systems handling complex validation rules like geospatial indexing where race conditions can create exploitable memory corruption vulnerabilities.