CVE-2026-67628 in SQL Server
Summary
by MITRE • 10/15/2026
Out-of-bounds read in SQL Server allows an authorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability described constitutes an out-of-bounds read flaw within Microsoft SQL Server, classified under the Common Weakness Enumeration as CWE-125: Out-of-Bounds Read. This type of memory safety error occurs when software attempts to access data beyond the boundaries of a designated buffer or array structure without performing adequate validation checks on input indices or lengths. In the context of database management systems like SQL Server, such flaws often arise during the processing of complex query structures, specific T-SQL commands, or internal engine operations that handle large datasets or intricate logical expressions. When an attacker triggers this condition by sending a specially crafted network request to the vulnerable instance, the application reads memory locations that are not allocated for its current operation. This behavior violates fundamental principles of secure coding and memory isolation, leading to unpredictable system states depending on what data resides in those adjacent memory regions at the time of execution.
From an operational perspective, the primary impact of this vulnerability is information disclosure rather than immediate code execution or denial of service. Because the flaw involves reading unallocated or sensitive memory contents, it can result in the leakage of internal application state, cryptographic keys, authentication tokens, or other proprietary data stored within the server's process space. An authorized attacker who has established a connection to the SQL Server instance can exploit this weakness over the network by crafting specific payloads that trigger the erroneous read operation. The leaked information may provide critical insights into the system architecture, facilitate further lateral movement, or allow for more sophisticated attacks such as heap spraying or bypassing security controls that rely on memory randomization techniques like ASLR. While the attacker requires valid credentials to initiate the connection, the ability to exfiltrate internal data significantly compromises the confidentiality and integrity of the database environment.
This vulnerability aligns with MITRE ATT&CK technique T1005: Data from Local System, specifically within the context of remote exploitation via network services. The attack vector is classified as Network (ATT&CK ID TA0001), indicating that the exploit can be delivered remotely if the SQL Server service is exposed to untrusted networks or if an authenticated user has access through a compromised endpoint. Defense in depth strategies are essential for mitigating this risk, starting with the immediate application of vendor-provided security patches and updates to ensure all known memory safety issues are resolved. Additionally, organizations should enforce strict network segmentation policies to limit direct exposure of SQL Server instances to untrusted zones, ensuring that only authorized management stations or specific application servers can communicate directly with the database engine. Implementing robust input validation at the application layer before queries reach the server and utilizing parameterized queries can also reduce the attack surface by preventing malformed inputs from reaching vulnerable code paths within the database engine itself.