CVE-2026-114652 in C# Driver
Summary
by MITRE • 10/23/2026
A data-query-logic neutralization weakness in the update-statement construction component of the MongoDB C# Driver can cause application-supplied values to be interpreted as query/update logic rather than as literal data. An application user who can influence the content of values that the application passes into the affected builder surface, without any special privilege beyond ordinary read-write application access, may cause stored data to be modified or removed in ways the application never intended. The result is unauthorized integrity impact on the affected application data; there is no direct loss of confidentiality or availability of the database service.
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Analysis
by VulDB Data Team • 10/23/2026
The vulnerability described constitutes a critical injection flaw within the MongoDB C# Driver, specifically affecting its update-statement construction component. This weakness arises from a failure in proper neutralization of user-supplied input before it is incorporated into data-query logic. In secure software design, there must be strict separation between code and data; however, this vulnerability allows application-supplied values to be interpreted as executable query or update commands rather than being treated strictly as literal data fields. This misinterpretation occurs because the driver's builder surface does not adequately sanitize or escape inputs that influence the structure of the MongoDB update operations, creating a pathway for attackers to inject malicious logic into database queries.
From an operational perspective, this flaw enables unauthorized integrity impacts on application data without requiring elevated privileges beyond standard read-write access. An attacker who can control input values passed through vulnerable endpoints in the application layer can manipulate how updates are constructed and executed against the MongoDB instance. By injecting specific operators or field modifications that were not intended by the original application logic, an adversary can alter existing records, delete critical information, or introduce malformed data structures. The impact is primarily focused on data integrity rather than confidentiality or availability, as the attacker does necessarily need to exfiltrate sensitive information nor disrupt the database service itself, but they do gain the ability to corrupt the state of the application's persistent storage in ways that bypass intended business logic constraints.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-94, which describes Improper Control of Generation of Code or SQL Injection, often referred to broadly as NoSQL injection when applied to document databases like MongoDB. The specific mechanism involves the improper neutralization of special elements used in a query language, allowing an attacker to change the intended meaning of commands sent to the database engine. In the context of MITRE ATT&CK, this behavior maps to techniques involving data manipulation and potentially command injection within application layers, specifically falling under tactics related to persistence or impact depending on whether the injected logic is designed to maintain access or cause damage. The lack of proper input validation in the driver's update builder represents a significant deviation from secure coding practices recommended for interacting with NoSQL databases.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. Developers should immediately upgrade the MongoDB C# Driver to a version where this specific construction flaw has been patched, ensuring that all input values are properly escaped or parameterized before being passed into update statements. Application code reviewing processes should be implemented to audit any usage of dynamic query builders, particularly those accepting user-controlled parameters. Furthermore, adopting strict schema validation within the application layer can help detect and reject malformed data structures before they reach the database driver. Implementing principle of least privilege for database accounts used by the application also limits the potential blast radius if such an injection were to occur in other unpatched components, ensuring that even successful manipulation is confined to specific collections or databases with limited scope.