Microsoft May 2025 Patch Tuesday – Overview and Analysis

Microsoft’s May 2025 Patch Tuesday has arrived, delivering critical security updates and fixes for 71 vulnerabilities across a broad spectrum of its software ecosystem. This month’s release includes five vulnerabilities rated as Critical and 66 classified as Important, addressing security concerns in widely-used products like Windows, Azure, .NET, Visual Studio, and Microsoft Office.

Breakdown of Vulnerabilities

A total of 71 CVEs (Common Vulnerabilities and Exposures) were patched:

• 🛡️ 5 Critical vulnerabilities
• 🔍 66 Important vulnerabilities

A deeper dive into the types of vulnerabilities reveals:

• 🔓 28 Remote Code Execution (RCE) vulnerabilities – accounting for the majority of the critical issues
• 🔒 17 Elevation of Privilege (EoP) vulnerabilities
• 📄 15 Information Disclosure vulnerabilities
• 🚫 7 Denial of Service (DoS) vulnerabilities
• ⚠️ 2 Security Feature Bypass vulnerabilities
• 👥 2 Spoofing vulnerabilities

This distribution highlights Microsoft’s continued focus on fortifying its cloud infrastructure, desktop applications, and Windows OS against critical threats.

Critical Vulnerabilities Patched

The five critical vulnerabilities addressed this month include primarily RCE flaws that pose significant risks if exploited. Among them are vulnerabilities affecting Azure, Visual Studio, and Windows Hyper-V. These critical issues can allow attackers to execute arbitrary code, potentially taking full control of affected systems.

Actively Exploited Zero-Day Vulnerabilities

This month’s release also resolves five zero-day vulnerabilities actively exploited in the wild:

1. CVE-2025-30400 – Microsoft DWM Core Library Elevation of Privilege Vulnerability
   • This vulnerability allows attackers to elevate privileges through a use-after-free flaw in the Desktop Windows Manager (DWM) Core Library.
2. CVE-2025-32701 – Windows Common Log File System Driver Elevation of Privilege Vulnerability
   • Exploited as a zero-day, this flaw allows local privilege escalation by exploiting improper input validation in the CLFS Driver.
3. CVE-2025-32706 – Windows Common Log File System Driver Elevation of Privilege Vulnerability
   • Another zero-day in the CLFS Driver, exploited to elevate privileges locally.
4. CVE-2025-32709 – Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
   • A use-after-free vulnerability allowing local privilege escalation via the Ancillary Function Driver for WinSock.
5. CVE-2025-30397 – Scripting Engine Memory Corruption Vulnerability
   • This RCE vulnerability in Microsoft Scripting Engine can be exploited through type confusion to execute arbitrary code on a target machine.

Key Vulnerabilities to Watch

Several vulnerabilities patched in this cycle stand out due to their exploitation history and critical nature:

• CVE-2025-30385, CVE-2025-32701, and CVE-2025-32706 – All three target the Windows Common Log File System Driver, a component that has been repeatedly attacked over the past year.
• CVE-2025-30400 – The seventh EoP vulnerability patched in the DWM Core Library this year.
• CVE-2025-32702 – A Remote Code Execution vulnerability in Visual Studio that allows local code execution if exploited correctly.

Affected Microsoft Products

This month’s updates span across major Microsoft services and platforms, including:

• Windows OS Components: Hyper-V, Kernel, LDAP, NTFS, Remote Desktop, SMB, Win32K, etc.
• Azure Services: DevOps, Automation, File Sync, Storage Resource Provider.
• Microsoft Office Suite: Excel, Outlook, PowerPoint, SharePoint.
• Developer Tools: .NET, Visual Studio, VS Code.
• Security Solutions: Defender for Endpoint, Defender for Identity.

Conclusion

The May 2025 Patch Tuesday highlights Microsoft’s ongoing commitment to addressing critical security flaws that are actively exploited in the wild. System administrators and security teams are advised to prioritize patching of the actively exploited zero-days and critical RCE vulnerabilities to prevent potential breaches.

Stay safe, stay updated, and ensure your systems are patched to protect against these emerging threats.

Ref: https://msrc.microsoft.com/update-guide/releaseNote/2025-May

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