CVE-2026-67630 in SQL Server
Summary
by MITRE • 09/08/2026
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 • 09/08/2026
The vulnerability described constitutes a critical security flaw within Microsoft SQL Server, specifically categorized as an out-of-bounds read error. This type of memory corruption issue arises when the software reads data from a memory location that is outside the intended buffer boundaries. In the context of database management systems like SQL Server, such errors often occur during the processing of complex queries or specific administrative commands where input validation and bounds checking mechanisms fail to adequately constrain access requests. The core technical flaw lies in the improper handling of array indices or pointer arithmetic within the server's internal code paths, allowing a process to retrieve data from adjacent memory regions that were not intended for public exposure. This misalignment between expected buffer limits and actual read operations creates an avenue for unauthorized information disclosure.
From a threat actor perspective, this vulnerability is particularly dangerous because it can be exploited by an authenticated user over the network. The requirement for authorization does not mitigate the severity of the risk; rather, it highlights that any legitimate account with sufficient privileges to interact with the database engine could potentially trigger the flaw. By crafting specific malicious inputs or query structures, an attacker can induce SQL Server to read memory contents beyond the allocated buffer. This action results in the leakage of sensitive data residing in those adjacent memory locations. The disclosed information may include internal server states, cached credentials, encryption keys, or other proprietary data structures that are critical to the integrity and security of the database environment. Such leaks provide attackers with valuable intelligence for further exploitation phases, including privilege escalation or lateral movement within a networked infrastructure.
The operational impact of this vulnerability extends beyond simple data leakage. The disclosure of internal memory contents can compromise the confidentiality guarantees provided by SQL Server's encryption mechanisms if cryptographic keys are exposed in plaintext during processing. Furthermore, consistent exposure to such errors may lead to service instability or crashes as the server attempts to process corrupted state information derived from leaked context. For organizations relying on SQL Server for mission-critical applications, this vulnerability represents a significant risk to data confidentiality and system availability. It undermines trust in the database engine's ability to isolate processes and protect sensitive assets from even authorized but potentially compromised user accounts.
To mitigate the risks associated with this out-of-bounds read vulnerability, immediate action is required to apply vendor-provided security patches that address the underlying memory management flaws. Administrators should ensure that all SQL Server instances are updated to the latest cumulative update or service pack released by Microsoft, which includes fixes for known buffer handling issues. In addition to patching, implementing strict network segmentation and firewall rules can limit exposure to untrusted networks, ensuring that only authorized clients can connect to the database engine. Principle of least privilege should be rigorously enforced; administrative accounts must not be used for routine application connections, thereby reducing the attack surface available to potential exploiters. Continuous monitoring of SQL Server logs for anomalous query patterns or unusual memory usage spikes can also aid in early detection and response to exploitation attempts.
This vulnerability aligns with Common Weakness Enumeration (CWE) identifier CWE-125, which describes out-of-bounds read operations that allow attackers to access sensitive information from adjacent memory spaces. It is also relevant to the MITRE ATT&CK framework under techniques related to Credential Access and Discovery, specifically where an attacker leverages software vulnerabilities to gather intelligence about the target environment. Understanding these classifications helps security teams prioritize remediation efforts based on established industry standards for vulnerability management and risk assessment protocols.