Microsoft has released its May 2025 security update package, addressing 78 vulnerabilities across its product ecosystem, including five critical zero-day flaws that threat actors were actively exploiting. This comprehensive security update underscores the increasing sophistication of cyber threats targeting Windows environments and cloud infrastructure.
Critical Privilege Escalation Vulnerabilities Under Active Exploitation
Among the most severe issues patched, four zero-day vulnerabilities enable attackers to elevate their privileges to SYSTEM level, potentially gaining complete control over affected systems. The most critical of these, CVE-2025-30400, affecting the DWM Core Library in Windows Server 2025, received a CVSS score of 7.8. Three additional privilege escalation flaws (CVE-2025-32701, CVE-2025-32706, and CVE-2025-32709) impact crucial Windows components, including the Common Log File System and Ancillary Function Driver for WinSock.
Browser-Based Remote Code Execution Threat
The fifth actively exploited vulnerability, CVE-2025-30397 (CVSS 7.5), presents a significant risk through Microsoft’s scripting engine. Attackers can leverage this flaw to execute remote code via Microsoft Edge or Internet Explorer when users visit maliciously crafted websites. This vulnerability highlights the continued importance of browser security in enterprise environments.
Azure DevOps Critical Authentication Bypass
A particularly concerning discovery is the CVE-2025-29813 vulnerability in Azure DevOps Server, which received the maximum CVSS score of 10.0. This authentication bypass flaw could potentially expose entire development pipelines to unauthorized access. Microsoft has already implemented fixes in their cloud infrastructure, requiring no additional action from cloud service users.
Additional Security Considerations
The update also addresses two publicly disclosed vulnerabilities: CVE-2025-26685 in Microsoft Defender for Identity, which could enable local network spoofing attacks, and CVE-2025-32702 in Visual Studio, potentially allowing remote code execution in development environments.
Security professionals emphasize the critical nature of this update, particularly given the active exploitation of multiple zero-day vulnerabilities. Organizations should prioritize the immediate deployment of these patches across their infrastructure. Regular system updates and robust patch management procedures remain fundamental to maintaining strong cybersecurity posture. Security teams should also implement additional protective measures, including network segmentation and enhanced monitoring, while the patches are being deployed.
