Heap-based Buffer Overflow in Windows NTFS

Executive Summary

CVE-2026-49797 is a heap-based buffer overflow vulnerability in Windows NTFS. This flaw allows an unauthorized attacker to execute arbitrary code on a vulnerable system locally. A heap-based buffer overflow occurs when a program writes more data to a buffer than it can hold, corrupting or overwriting adjacent memory, which can lead to code execution.

The vulnerability is classified as a local attack vector, meaning the attacker must have access to the target system to exploit it. The CVSS v3.1 base score is 7.8, indicating a high severity level due to its potential impact on confidentiality, integrity, and availability.

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Impact Analysis

If exploited, this vulnerability could have several impacts on you or your organization:

• An attacker could execute arbitrary code on your system, potentially gaining full control over it.
• Sensitive data stored on the affected system could be accessed, modified, or deleted.
• The attacker could install malware, create backdoors, or perform other malicious actions to maintain persistence on the system.
• The vulnerability could be used as a stepping stone for further attacks within your network, especially if the compromised system has elevated privileges.

Since the attack requires local access, the risk is higher in environments where multiple users share systems or where physical security is weak.

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Compliance Impact

This vulnerability could impact compliance with several standards and regulations, depending on the context of its exploitation:

• GDPR (General Data Protection Regulation): If the vulnerability leads to unauthorized access or disclosure of personal data, it could result in a breach of GDPR requirements. Organizations may face fines or penalties for failing to protect personal data adequately.
• HIPAA (Health Insurance Portability and Accountability Act): If the affected system processes or stores protected health information (PHI), exploitation of this vulnerability could lead to a breach of HIPAA's security and privacy rules, resulting in regulatory action.
• Other standards like ISO 27001, NIST, or PCI DSS may also be impacted if the vulnerability affects systems handling sensitive or regulated data. Failure to patch or mitigate the vulnerability could be seen as a lapse in maintaining required security controls.

Organizations should assess whether this vulnerability affects systems within the scope of these regulations and take appropriate steps to mitigate the risk to maintain compliance.

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Detection Guidance

The provided context does not include specific detection methods or commands for identifying the heap-based buffer overflow vulnerability in Windows NTFS (CVE-2026-49797) on a network or system.

Typically, detection might involve using vulnerability scanning tools or checking for specific patches or updates from Microsoft. However, no explicit detection commands or tools are mentioned in the available resources.

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Mitigation Strategies

To mitigate CVE-2026-49797, apply the security update provided by Microsoft as soon as possible.

• Visit the Microsoft Update Guide for CVE-2026-49797 to download and install the latest patch.
• Ensure all systems running Windows NTFS are updated to the latest secure version.

If immediate patching is not feasible, consider implementing workarounds or additional security measures, such as restricting local access to vulnerable systems, though these are not specified in the provided context.

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