BlueHammer Vulnerability Exploited in Ransomware Attacks

The Microsoft Defender vulnerability CVE-2026-33825 was exploited in the wild as a zero-day before patches were released. The post BlueHammer Vulnerability Exploited in Ransomware Attacks appeared first on SecurityWeek .

The article reports that the Microsoft Defender vulnerability CVE-2026-33825 (BlueHammer), a local privilege escalation flaw in Defender’s remediation/update logic, was exploited in the wild as a zero-day in ransomware campaigns before Microsoft released patches.[1][7][9] Attackers leveraged this TOCTOU-style race condition to escalate from low-privileged accounts to SYSTEM on fully patched Windows systems, turning a core security product into an attack vector.[3][5] From a CyberSE.AI perspective, this represents a critical AI/endpoint security supply chain risk, since organizations depend on Defender and similar security/AI-enhanced services as trusted components; when those components are vulnerable, they can silently undermine broader AI-driven detection and response workflows. Practically, organizations should treat endpoint security platforms and embedded AI services as part of their SBOM, enforce rapid patching and version verification, and integrate continuous red teaming and readiness assessments to detect when "defensive" components become exploitable choke points in their AI security stack.