CVE-2026-96848 in Windows
Summary
by MITRE • 10/14/2026
Buffer over-read in Windows Win32 Kernel Subsystem allows an authorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified involves a buffer over-read condition within the Windows Win32 Kernel Subsystem, specifically affecting components responsible for handling inter-process communication and system-level data structures. This flaw arises when the subsystem fails to properly validate the length of input buffers before reading from them, leading to access beyond the allocated memory boundaries. While typically associated with more severe exploitation vectors such as arbitrary code execution or privilege escalation in other contexts, this specific instance is characterized by its ability to disclose sensitive information rather than allow for direct control flow hijacking. The root cause lies in insufficient boundary checks during the processing of certain kernel-mode requests, where data from adjacent memory regions may be inadvertently exposed to user-space applications that have legitimate access rights but lack proper sanitization mechanisms.
From a technical perspective, this issue falls under the category of CWE-126, which denotes Buffer Over-read vulnerabilities. The attack vector is classified as local (CWE-409), requiring an attacker to have authenticated access to the system before exploitation can occur. This aligns with MITRE ATT&CK technique T1005, Data from Local System, where adversaries seek to gather information directly from a compromised host without necessarily escalating privileges immediately. The vulnerability is triggered when specific Win32 API calls are made that interact with kernel structures containing sensitive data such as session tokens, cryptographic keys, or internal process states. Because the read operation does not respect memory allocation limits, it retrieves uninitialized or unrelated memory contents, which can then be returned to the calling application through standard output channels.
The operational impact of this vulnerability is primarily centered on information disclosure rather than system compromise in its immediate form. An authorized attacker who exploits this flaw could potentially extract sensitive data that was intended to remain isolated within kernel space. This might include partial views of other processes' memory, internal configuration details, or cryptographic material used for securing communications between subsystems. Although the attacker must already possess valid credentials and local access, the ability to leak such information can facilitate further attacks by providing context necessary for privilege escalation attempts or lateral movement within a networked environment. The severity is mitigated somewhat by the requirement for authentication, but it remains significant due to the potential exposure of high-value secrets that could undermine overall system integrity.
Mitigation strategies should focus on both immediate patching and long-term architectural improvements. Microsoft has addressed this issue through security updates that enforce stricter bounds checking within the Win32 Kernel Subsystem routines responsible for buffer handling. Administrators are advised to apply these patches promptly to close the information leak vector. Additionally, developers implementing custom kernel extensions or drivers should review their code for similar patterns of unchecked memory access, ensuring that all read operations verify buffer lengths against allocated sizes before execution. Implementing defense-in-depth measures such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) can also help mitigate the potential consequences by making it more difficult to predict or utilize leaked memory addresses effectively. Regular security audits and static code analysis tools configured to detect CWE-126 patterns are recommended to prevent recurrence in future software versions.