CVE-2026-85356 in Windows
Summary
by MITRE • 10/14/2026
Out-of-bounds read in Windows Volume Manager Extension Driver allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified within the Microsoft Windows Volume Manager Extension Driver represents a critical security flaw that stems from improper memory management practices during data access operations. Specifically, this is classified as an out-of-bounds read error, which corresponds to CWE-125 in the Common Weakness Enumeration standard. This type of defect occurs when software reads data beyond the boundaries of allocated buffers or arrays, often due to insufficient validation of input parameters such as array indices or buffer lengths before accessing memory locations. In the context of the Volume Manager Extension Driver, this flaw likely arises during the processing of volume-related requests where the driver fails to adequately verify that requested read operations remain within the valid bounds of the underlying data structures.
From an operational perspective, while out-of-bounds reads are traditionally associated with information disclosure rather than direct code execution, their impact in kernel-mode drivers is significantly more severe due to the elevated privileges inherent to such components. An authorized attacker who has already gained a foothold on the system can exploit this vulnerability to read sensitive data from arbitrary memory locations within the kernel address space. This capability allows for the extraction of cryptographic keys, session tokens, or other high-value secrets that are not accessible through normal user-mode APIs. Furthermore, in many modern operating systems including Windows, reading specific kernel structures can provide critical information about memory layout and security mitigations such as Kernel Address Space Layout Randomization (KASLR) offsets, which serves as a crucial step for subsequent exploitation stages aimed at achieving full system compromise.
The attack vector for this vulnerability is local, requiring the attacker to have valid authentication credentials on the target machine before they can attempt to trigger the flaw within the Volume Manager Extension Driver. This aligns with MITRE ATT&CK technique T1068 Exploitation for Privilege Escalation, specifically under sub-techniques involving exploitation of trusted services or drivers. The presence of this vulnerability indicates a gap in the driver's input validation logic, allowing maliciously crafted IOCTL requests to cause the kernel to perform unauthorized memory reads. This can lead to partial information leakage that aids in bypassing security controls and potentially facilitates further privilege escalation attacks if combined with other vulnerabilities such as use-after-free or heap corruption issues within the same subsystem.
To mitigate this risk, organizations must ensure that all systems running affected versions of Windows are updated with the latest cumulative security patches provided by Microsoft. These updates typically include code changes that enforce stricter bounds checking and input validation routines within the Volume Manager Extension Driver. Administrators should also implement strict access controls to limit which users or services can interact with volume management interfaces, thereby reducing the attack surface available to potential local attackers. Additionally, deploying endpoint detection and response solutions capable of monitoring for anomalous driver behavior or unusual memory access patterns can help in detecting exploitation attempts in real-time. Regular auditing of system logs for signs of unauthorized privilege escalation activities is also recommended as a defensive measure against such kernel-level vulnerabilities.