Improper Link Resolution Leading to Privilege Escalation in Windows RRAS

Executive Summary

CVE-2026-49791 is a vulnerability in the Windows Routing and Remote Access Service (RRAS). It involves improper link resolution before file access, also known as 'link following'. This flaw allows an authorized attacker with local access to exploit the system and elevate their privileges.

Specifically, the vulnerability occurs when the RRAS service does not properly validate or resolve symbolic links or other types of links before accessing files. An attacker could manipulate these links to gain higher privileges on the system.

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Impact Analysis

If you are using a system with the Windows Routing and Remote Access Service (RRAS) enabled, this vulnerability could impact you in the following ways:

• An authorized attacker with local access to your system could exploit this vulnerability to elevate their privileges.
• Once privileges are elevated, the attacker could perform actions with higher permissions, such as installing malicious software, accessing or modifying sensitive data, or disrupting system operations.
• This could lead to unauthorized control over the affected system, potentially compromising the security and integrity of your network or data.

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Compliance Impact

This vulnerability could impact compliance with common standards and regulations in the following ways:

• GDPR: If the affected system processes or stores personal data of EU citizens, a successful exploitation of this vulnerability could lead to unauthorized access or modification of that data. This may result in a breach of GDPR requirements related to data protection and security, potentially leading to fines or legal consequences.
• HIPAA: For organizations handling protected health information (PHI), this vulnerability could allow an attacker to gain elevated privileges and access sensitive patient data. This would violate HIPAA's Security Rule, which mandates safeguards to protect the confidentiality, integrity, and availability of PHI.
• Other standards: Many compliance frameworks, such as ISO 27001 or NIST, require organizations to maintain secure systems and protect against unauthorized access. Exploitation of this vulnerability could indicate a failure to meet these requirements, potentially leading to non-compliance.

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Mitigation Strategies

Apply the security update provided by Microsoft for CVE-2026-49791. The update addresses the improper link resolution issue in Windows Routing and Remote Access Service (RRAS) that could allow privilege elevation.

To obtain the update, visit the Microsoft Security Response Center (MSRC) update guide for this CVE.

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