Microsoft Brokering File System Double Free Local Privilege Escalation

Executive Summary

CVE-2026-50361 is a vulnerability in the Microsoft Brokering File System. It involves a 'double free' error, which occurs when a program incorrectly frees the same memory location twice. This can lead to memory corruption and unpredictable behavior in the system.

An authorized attacker with local access to the system can exploit this vulnerability to elevate their privileges. This means they could gain higher-level permissions than they are supposed to have, potentially allowing them to perform actions like installing software, accessing restricted data, or modifying system configurations.

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Detection Guidance

The provided context does not include specific detection methods or commands for identifying the presence of CVE-2026-50361 on a network or system. Detection typically involves checking for vulnerable versions of the Microsoft Brokering File System or using security tools that can identify memory corruption issues like double free vulnerabilities.

For accurate detection guidance, refer to Microsoft's official documentation or security advisories, which may provide updated tools or scripts to scan for this vulnerability.

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Impact Analysis

If you are using a system with the Microsoft Brokering File System, this vulnerability could allow an attacker with local access to elevate their privileges on your system.

• An attacker could gain administrative or higher-level access, allowing them to take control of your system.
• They could install malicious software, steal sensitive data, or modify system settings without your knowledge.
• The vulnerability could be used to bypass security measures, leading to further exploitation of your system or network.

Since the attacker needs local access, the risk is higher in environments where multiple users share a system or where physical access to machines is not tightly controlled.

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Compliance Impact

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

• GDPR (General Data Protection Regulation): If the vulnerability is exploited to access or exfiltrate personal data of EU citizens, it could lead to a data breach. Organizations are required to protect personal data under GDPR, and failure to do so could result in significant fines and legal consequences.
• HIPAA (Health Insurance Portability and Accountability Act): In healthcare environments, if the vulnerability is used to access protected health information (PHI), it could constitute a breach under HIPAA. Covered entities must ensure the confidentiality, integrity, and availability of PHI, and a breach could lead to penalties.
• Other standards like ISO 27001, NIST, or PCI DSS may also be affected if the vulnerability leads to unauthorized access or control over systems handling sensitive information. Compliance with these standards often requires maintaining strong access controls and protecting against privilege escalation attacks.

Organizations should assess the risk posed by this vulnerability and take appropriate measures to mitigate it to avoid potential compliance violations.

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Mitigation Strategies

Based on the provided context, the following immediate steps are recommended to mitigate CVE-2026-50361:

• Apply the latest security updates or patches provided by Microsoft for the Microsoft Brokering File System. Refer to the official Microsoft update guide for this CVE.
• Restrict local access to systems running the vulnerable component to minimize the risk of exploitation by an authorized attacker.
• Monitor Microsoft's security advisories for additional guidance or workarounds if a patch is not immediately available.

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