CVE-2026-120959 in Atlas SQL
Summary
by MITRE • 11/03/2026
A memory-handling flaw in the MongoDB Atlas SQL ODBC Driver can cause values returned for a query to be written outside the bounds of a buffer provided by the calling application. A party able to influence the values a query returns may cause data to be placed at an unintended location in the client application's memory, which may result in unintended modification of that memory or termination of the client process. Reaching this condition depends on a specific, application-chosen way of requesting several result rows at once.
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified within the MongoDB Atlas SQL ODBC Driver represents a critical memory safety issue rooted in improper bounds checking during buffer management operations. Specifically, the flaw occurs when the driver processes query results that are retrieved using an application-specific method for fetching multiple result rows simultaneously. In this scenario, the internal logic responsible for mapping database values to client-side data structures fails to validate whether the target buffer provided by the calling application has sufficient capacity to hold the incoming data. This lack of rigorous boundary verification allows the driver to write memory contents beyond the allocated limits of the destination buffer, creating a classic heap-based or stack-based buffer overflow condition depending on how the caller allocates its workspace.
From a technical perspective, this defect aligns with Common Weakness Enumeration category CWE-120, which describes Buffer Copy without Checking Size of Input. The root cause lies in the assumption that the input data size will always fit within pre-allocated memory regions provided by the host application. When an attacker or malicious actor can influence the values returned by a query—perhaps through crafted database entries or manipulated result sets—they can trigger this overflow condition. By supplying oversized payloads, the driver writes arbitrary data to adjacent memory locations that are not part of the intended buffer structure. This behavior violates fundamental principles of secure coding and memory isolation, allowing for potential control flow hijacking if the overwritten memory contains critical pointers or return addresses.
The operational impact of exploiting this vulnerability is severe, ranging from denial of service to remote code execution. If an attacker successfully triggers the out-of-bounds write, they may corrupt adjacent heap metadata, leading to immediate termination of the client process through a segmentation fault or access violation. This results in a reliable Denial of Service against any application relying on the MongoDB Atlas SQL ODBC Driver for data retrieval. More critically, if the memory layout permits it and specific exploitation techniques are applied, such as overwriting function pointers or exception handlers, an attacker could achieve arbitrary code execution within the context of the client process. This elevates a simple data corruption bug into a high-severity security threat capable of compromising system integrity and confidentiality.
In terms of industry frameworks, this vulnerability maps to MITRE ATT&CK techniques associated with initial exploitation and privilege escalation via memory corruption. It falls under the broader category of software vulnerabilities that facilitate lateral movement or persistence if the client application runs with elevated privileges. The specific mechanism of influencing query results suggests an attack vector where the database itself serves as a source for malicious payloads, highlighting the importance of treating data from external sources as untrusted until validated by both the driver and the host application.
Mitigation strategies must focus on immediate patching and defensive coding practices. Organizations utilizing this driver should apply vendor-provided updates that enforce strict size validation before performing memory writes. Developers integrating the ODBC Driver into their applications should implement additional sanity checks, ensuring that buffer sizes are explicitly verified against expected data lengths prior to invocation of fetch operations. Furthermore, enabling Address Space Layout Randomization and other modern exploit mitigation techniques can reduce the likelihood of successful code execution even if a buffer overflow occurs. Regular security audits focusing on memory management routines in database connectivity layers are essential to prevent similar flaws from persisting in production environments.