Microsoft August 2026 Patch Tuesday fixes 400 flaws, 3 zero-days

Microsoft's August 2026 Patch Tuesday revealed a massive attack surface with 400 vulnerabilities, three of which were zero-days — one actively exploited by North Korea's Lazarus Group to deploy the FudModule kernel-mode rootkit before a patch was even available. This incident underscores the danger of zero-day exploitation windows, where threat actors leverage undisclosed flaws to gain deep system access (kernel-level) before defenders can respond. The use of a rootkit means attackers can persist invisibly, evade detection, and maintain long-term footholds within compromised environments. Organizations that delay patch deployment or lack compensating controls are especially vulnerable during this critical window between public disclosure and patch application.