CVE-2026-50422 in Windows
Summary
by MITRE • 07/14/2026
Out-of-bounds read in Windows NTFS allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical out-of-bounds read flaw within the Windows NTFS file system implementation that enables authenticated local attackers to escalate their privileges from standard user level to SYSTEM level. The issue stems from improper bounds checking during NTFS metadata processing, specifically when handling certain file system structures or directory entries. When a malicious user with legitimate login credentials attempts to access or manipulate specific NTFS file system objects, the kernel-level driver fails to validate array indices or buffer limits, resulting in memory access violations that can be exploited to read beyond allocated memory boundaries.
The technical implementation of this vulnerability involves the NTFS file system driver's handling of file allocation tables, master file table entries, or other internal data structures where insufficient input validation occurs. Attackers can construct malicious file system objects or manipulate existing ones to trigger the out-of-bounds read condition, potentially allowing them to access sensitive kernel memory locations that contain credential information, security descriptors, or other privileged data structures. This flaw operates at the kernel level within the ntfs.sys driver component, making it particularly dangerous as it bypasses standard user-mode protections and operates within the most privileged execution context of the operating system.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential information disclosure and system stability compromise. Successful exploitation can result in unauthorized access to sensitive system data, including password hashes, security tokens, or other authentication credentials stored in kernel memory. Additionally, the out-of-bounds read may cause system crashes or unpredictable behavior when the corrupted memory access leads to invalid memory dereferences, potentially enabling denial of service attacks or creating opportunities for further exploitation through chained vulnerabilities. The local nature of this attack means that attackers must first establish a valid user session on the target system, but once achieved, they can leverage this vulnerability to gain complete system control.
Mitigation strategies for this vulnerability encompass multiple layers of defense including immediate patch application from Microsoft as part of regular security updates, implementation of least privilege principles to limit user account capabilities, and deployment of enhanced monitoring solutions to detect anomalous file system access patterns. System administrators should implement strict access controls and regularly audit user permissions to minimize the attack surface available to potential exploiters. Network segmentation and endpoint protection solutions can provide additional detection capabilities for suspicious behavior related to NTFS file system manipulation. Organizations must also consider implementing exploit prevention technologies that monitor for known exploitation patterns associated with out-of-bounds read vulnerabilities, which aligns with mitigations recommended in the mitre ATT&CK framework under privilege escalation techniques. The vulnerability classification aligns with CWE-129 and CWE-787 categories, representing improper input validation and out-of-bounds access issues respectively, while the exploitation methodology corresponds to techniques described in the ATT&CK matrix for local privilege escalation through kernel exploits.