Stack-based Buffer Overflow in Windows NTFS

Impact Analysis

This vulnerability can impact you in several ways if you are using a system with Windows NTFS:

• An attacker with local access and low privileges could exploit this flaw to gain elevated privileges on your system.
• Once privileges are elevated, the attacker could execute arbitrary code, install malware, or access sensitive data.
• The high impact on confidentiality, integrity, and availability means the attacker could steal data, modify system files, or disrupt system operations.

This is particularly concerning for systems handling sensitive information or critical operations, as it could lead to further compromise of the network or data breaches.

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Executive Summary

CVE-2026-49789 is a stack-based buffer overflow vulnerability in Windows NTFS. This flaw allows an authorized attacker with local access to exploit the system and elevate their privileges. A buffer overflow occurs when a program writes more data to a buffer than it can hold, which can corrupt adjacent memory and allow arbitrary code execution or privilege escalation.

In this case, the vulnerability is specific to the Windows NTFS file system, meaning the attacker must have some level of authorization on the system to exploit it. The CVSS vector (AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H) indicates it requires local access, low attack complexity, low privileges, and user interaction, but it can lead to high impacts on confidentiality, integrity, and availability.

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Compliance Impact

This vulnerability can affect compliance with common standards and regulations in the following ways:

• GDPR: If the system processes personal data of EU citizens, a successful exploit could lead to unauthorized access or disclosure of this data. GDPR requires organizations to implement appropriate security measures to protect personal data, and a privilege escalation vulnerability could be seen as a failure to meet these requirements, potentially resulting in fines or penalties.
• HIPAA: For organizations handling protected health information (PHI), this vulnerability could lead to unauthorized access or modification of PHI. HIPAA requires safeguards to ensure the confidentiality, integrity, and availability of PHI. A breach resulting from this vulnerability could lead to non-compliance and associated penalties.
• Other standards: Many compliance frameworks (e.g., ISO 27001, NIST, PCI DSS) require organizations to maintain secure systems and protect against unauthorized access. This vulnerability could indicate a failure to patch known security flaws or implement adequate access controls, leading to non-compliance.

Organizations should address this vulnerability promptly to avoid potential compliance violations and the associated legal or financial consequences.

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Detection Guidance

The provided context does not include specific detection methods or commands for identifying CVE-2026-49789 on a network or system. This vulnerability involves a stack-based buffer overflow in Windows NTFS, which may require specialized tools or updates from Microsoft to detect.

To check for vulnerable systems, you may need to rely on Microsoft-provided updates or security tools, such as Windows Update, Microsoft Defender, or other vulnerability scanners that support CVE detection. Monitoring for unusual privilege escalation attempts or NTFS-related crashes could also indicate exploitation attempts.

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Mitigation Strategies

Based on the provided context, the following steps can help mitigate CVE-2026-49789:

• Apply the latest security updates from Microsoft as soon as they are available. Refer to the Microsoft Update Guide for CVE-2026-49789 for patches.
• Restrict local access to systems to only authorized users, as the vulnerability requires local access to exploit.
• Monitor systems for unusual privilege escalation activity or NTFS-related errors, which may indicate exploitation attempts.
• Use Microsoft Defender or other endpoint protection tools to detect and block potential exploitation attempts.

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