New PoC Exploit for NTLM Reflection Bypass Vulnerability on Windows Server

A proof-of-concept (PoC) exploit has been released for a NTLM reflection bypass vulnerability, tracked as CVE-2026-24294, which allows attackers to gain SYSTEM-level access on Windows Server 2025. This vulnerability arises from design flaws that were not fully addressed by the previous patch for CVE-2025-33073. The original mitigation only covered the SMB client path, leaving other vectors open for exploitation. The PoC was made public on April 30, 2026, and raises significant concerns about the effectiveness of Microsoft's authentication hardening measures. Organizations using Windows Server 2025 are at risk, particularly those that have not implemented additional security layers. The release of the PoC has prompted urgent advisories for system administrators to assess their environments and apply necessary mitigations.

Key Points: • CVE-2026-24294 allows SYSTEM access via NTLM reflection bypass on Windows Server 2025. • The vulnerability exploits unaddressed design flaws from the previous CVE-2025-33073 patch. • Immediate action is recommended for organizations to secure their Windows Server environments.