CVE-2026-92757 in MongoDB Entity Framework Core Provider
Summary
by MITRE • 09/17/2026
Applications built on MongoDB Entity Framework Core Provider which place a database name in the connection string may inadvertently disable field level encryption.
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Analysis
by VulDB Data Team • 09/17/2026
The vulnerability described involves a critical configuration flaw within applications utilizing the MongoDB Entity Framework Core Provider, specifically concerning the interaction between connection string parameters and client-side data protection mechanisms. When developers construct database connections by embedding specific identifiers such as the target database name directly into the connection URI, they inadvertently trigger a logic path that bypasses or disables field-level encryption features provided by the underlying driver. This issue stems from how the provider parses configuration options during initialization; certain legacy or simplified parsing routines may prioritize standard connectivity parameters over security-specific settings if not explicitly overridden in higher-level application code. Consequently, sensitive data intended to be encrypted at rest within specific fields is transmitted and stored in plaintext, exposing it to unauthorized access should an attacker gain read privileges to the database storage layer.
From a technical perspective, this flaw represents a misconfiguration that leads to a failure in implementing cryptographic protections as designed by the application architecture. The Entity Framework Core Provider acts as an abstraction layer between the application logic and the MongoDB driver. If the connection string format does not explicitly signal the need for encryption context initialization or if specific flags are omitted due to reliance on default behaviors triggered by simple database name inclusion, the encryption middleware is never instantiated. This results in data being written directly to the storage engine without applying the necessary transformation algorithms defined in the application's security policy. The root cause lies in the assumption that standard connection parameters imply full feature support, whereas modern MongoDB drivers often require explicit configuration objects or specific URI options to activate advanced features like client-side field-level encryption.
The operational impact of this vulnerability is severe, particularly for applications handling personally identifiable information, financial records, or other regulated data types. Since field-level encryption is typically employed to ensure compliance with standards such as GDPR, HIPAA, and PCI-DSS by limiting the exposure of sensitive fields even if the broader database is compromised, its absence creates a significant security gap. An attacker who exploits any subsequent vulnerability allowing them to query the database or exfiltrate data dumps will find that all protected fields are readable in plain text. This negates the primary defense-in-depth strategy intended to protect high-value assets and can lead to regulatory fines, loss of customer trust, and potential legal liabilities for the organization deploying the affected application.
To mitigate this risk, developers must audit their connection string configurations and ensure they explicitly enable field-level encryption through proper API calls or configuration objects rather than relying on implicit defaults derived from simple URI structures. It is recommended to use dedicated initialization routines that load encryption keys and define schema maps before establishing any database connections. Additionally, security teams should implement automated testing procedures that verify the presence of encrypted data in the storage layer after write operations are performed by the application. Regular code reviews focusing on data access layers can help identify instances where connection strings are constructed without adequate attention to security parameters. Adhering strictly to MongoDB's official documentation for client-side encryption setup, which emphasizes explicit configuration over implicit behavior, is essential to maintaining the integrity of sensitive data stores. This vulnerability aligns with CWE-923 Improper Restriction of Communication Between Components and highlights the importance of verifying that security controls are actively enforced rather than merely declared in configuration files.