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CVE-2026-50501 Microsoft CVE debrief

CVE-2026-50501 is a stack-based buffer overflow vulnerability in the Windows Resilient File System (ReFS). An unauthorized attacker could exploit this vulnerability to execute code locally. The vulnerability has a CVSS score of 7.8 and is classified as HIGH severity. It affects Windows 11 24H2, 25H2, 26H1, and Windows Server 2025. The vulnerability is caused by a stack-based buffer overflow, which occurs when more data is written to a buffer than it is designed to hold. This can allow an attacker to execute arbitrary code on the affected system. System administrators and users of affected systems should be aware of this vulnerability and take necessary precautions to protect their systems.

Vendor
Microsoft
Product
Windows 11 Version 24H2
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-22
Advisory published
2026-07-14
Advisory updated
2026-07-22

Who should care

System administrators and users of Windows 11 24H2, 25H2, 26H1, and Windows Server 2025 should be aware of this vulnerability and take necessary precautions to protect their systems. This includes applying patches or updates provided by Microsoft, using compensating controls such as firewalls and intrusion detection systems, and monitoring system logs for suspicious activity. Additionally, security teams should review and update their asset inventory to ensure all affected systems are accounted for and prioritize patching or mitigation efforts accordingly.

Technical summary

The vulnerability exists in the Windows Resilient File System (ReFS) and allows an unauthorized attacker to execute code locally. The vulnerability is caused by a stack-based buffer overflow and has been assigned a CVSS score of 7.8. Affected products include Windows 11 24H2, 25H2, 26H1, and Windows Server 2025. The vulnerability can be exploited by an attacker who can execute code on the affected system. The exact attack vector is not publicly disclosed, but it is believed to involve a specially crafted request to the ReFS.

Defensive priority

High

Recommended defensive actions

  • Apply patches or updates provided by Microsoft to vulnerable systems
  • Use compensating controls such as firewalls and intrusion detection systems
  • Monitor system logs for suspicious activity
  • Implement secure coding practices to prevent similar vulnerabilities
  • Review and update asset inventory to ensure all affected systems are accounted for

Evidence notes

The CVE record was published on 2026-07-14T18:17:57.137Z and was last modified on 2026-07-22T14:14:47.290Z. The NVD entry is currently Analyzed. The vulnerability exists in the Windows Resilient File System (ReFS) and allows an unauthorized attacker to execute code locally. The vulnerability is caused by a stack-based buffer overflow and has been assigned a CVSS score of 7.8. Affected products include Windows 11 24H2, 25H2, 26H1, and Windows Server 2025. However, detailed information about the vulnerability, such as the exact attack vector and potential mitigations, is limited. Defenders should verify the official CVE record and NVD entry for the most up-to-date information.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-14T18:17:57.137Z and has not been modified since then. The NVD entry is currently Analyzed.