CVE-2026-120952 in Atlas SQL ODBC Driver
Summary
by MITRE • 11/03/2026
An out-of-bounds write in the MongoDB Atlas SQL ODBC Driver may be triggered when a value of a particular database type is retrieved into a fixed-width client-side target. The driver produces a textual form of the value that is longer than the fixed target the ODBC interface defines, and copies it without limiting the copy to the target's real size. A database user with basic write privileges can influence part of the data written outside the target, which may corrupt memory in the application using the driver and cause that application to terminate unexpectedly.
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified involves a critical out-of-bounds write flaw within the MongoDB Atlas SQL ODBC Driver, specifically occurring during the retrieval of database values into fixed-width client-side buffers. This issue arises from an improper boundary check when converting internal data representations into their textual forms for transmission via the Open Database Connectivity interface. When a value associated with a specific database type is fetched, the driver generates a string representation that may exceed the length defined by the fixed-size buffer allocated on the client side. Instead of truncating the output or reallocating memory to accommodate the larger payload, the driver performs an unchecked copy operation, writing data beyond the boundaries of the designated target array. This fundamental lack of input validation and bounds checking allows for arbitrary write operations in adjacent memory regions, which constitutes a severe integrity violation within the application's execution environment.
From a technical perspective, this flaw aligns with CWE-787: Out-of-bounds Write, as it involves writing data to a memory location outside the intended buffer boundary. The vulnerability is particularly dangerous because it does not require high-level administrative privileges to exploit; rather, an attacker only needs basic write access to the database. By manipulating specific fields or injecting carefully crafted payloads that result in longer-than-expected textual representations of certain data types, an unauthorized user can trigger this memory corruption. The resulting overwrite affects adjacent memory structures, which may include control flow data such as return addresses on the stack or function pointers in heap metadata. This capability to corrupt arbitrary memory locations provides a potential pathway for remote code execution if the attacker can precisely predict the layout of the affected process's memory space and chain this write primitive with other exploitation techniques.
The operational impact of this vulnerability is significant, primarily manifesting as denial of service through application termination. When critical memory structures are overwritten, the host application utilizing the ODBC driver typically encounters an access violation or segmentation fault, leading to a crash. This disrupts business continuity and can lead to data loss if transactions were in progress at the time of the failure. Furthermore, while immediate exploitation for code execution is complex due to modern mitigations like ASLR and DEP, the potential for such escalation remains a severe risk. The vulnerability also undermines the integrity guarantees expected from database interactions, as an attacker could potentially alter application behavior or extract sensitive information by carefully crafting memory corruption scenarios that leak data before crashing the process.
To mitigate this risk, immediate action should be taken to apply vendor-provided patches that address the buffer handling logic within the MongoDB Atlas SQL ODBC Driver. Organizations must ensure that all instances of the driver are updated to versions where input validation and length checks have been implemented correctly. In addition to patching, defensive coding practices such as using safe string functions like strncpy or wcsncpy instead of unsafe equivalents like strcpy can prevent similar issues in custom integrations. Security teams should also monitor application logs for unexpected crashes or memory access violations that may indicate exploitation attempts. Furthermore, adher to the principle of least privilege is essential; database users interacting with applications via ODBC should be granted only the minimum permissions necessary, reducing the attack surface available to potential adversaries who might attempt to leverage this vulnerability as part of a broader ATT&CK technique involving application layer exploits or memory corruption for initial access and persistence.