Microsoft Warns of AD CS Vulnerability Let Attackers Deny Service Over a Network
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Microsoft has issued a security advisory regarding a new vulnerability in Active Directory<\/a> Certificate Services (AD CS) that could allow attackers to perform denial-of-service attacks over a network.\u00a0<\/p>\n The vulnerability, identified as CVE-2025-29968, affects multiple versions of Windows Server and has been assigned an \u201cImportant\u201d severity rating with a CVSS score of 6.5\/5.7.<\/p>\n The security flaw stems from improper input validation in Active Directory Certificate Services, a critical Windows role that enables organizations to issue and manage digital certificates for internal security purposes.\u00a0<\/p>\n The issue is categorized under CWE-20, Microsoft\u2019s technical documentation indicates that \u201cImproper input validation in Active Directory Certificate Services (AD CS) allows an authorized attacker to deny service over a network\u201d.<\/p>\n When exploited, attackers can cause the AD CS service to become unresponsive, potentially disrupting authentication processes, secure communications, and other certificate-dependent operations across an organization\u2019s infrastructure.<\/p>\n According to Microsoft\u2019s security bulletin, the vulnerability in the CVSS vector string indicates that this vulnerability can be exploited over a network with low attack complexity and requires low privileges.\u00a0<\/p>\n No user interaction<\/a> is necessary for exploitation, and while the vulnerability doesn\u2019t impact confidentiality or integrity , it can severely affect availability .<\/p>\n Researchers note that this vulnerability is concerning because an authenticated attacker with relatively low privileges could potentially disrupt certificate services across an entire organization.<\/p>\nMicrosoft AD CS Improper Input Validation Flaw<\/strong><\/h2>\n