Microsoft Releases Emergency Patch for Critical ASP.NET Core Vulnerability CVE-2026-40372
In April 2026, Microsoft identified a critical vulnerability (CVE-2026-40372) in ASP.NET Core's Data Protection API, which could allow unauthenticated attackers to escalate privileges to SYSTEM level by forging authentication cookies. This flaw, present in versions 10.0.0 through 10.0.6, stemmed from improper verification of cryptographic signatures, enabling attackers to bypass authentication mechanisms and gain unauthorized access to sensitive data. Microsoft promptly released an out-of-band update (version 10.0.7) to address this issue and advised users to update their systems immediately. This incident underscores the importance of timely patch management and vigilance in monitoring for security updates. The rapid response by Microsoft highlights the evolving nature of software vulnerabilities and the necessity for organizations to stay informed about potential threats to maintain robust security postures.
Kill Chain









