Microsoft released its September 2026 security updates, addressing two critical Windows elevation-of-privilege vulnerabilities: CVE-2026-85880 and CVE-2026-81963. Both vulnerabilities were exploited before their public disclosure on September 8. CVE-2026-85880 involves a heap-based buffer overflow in the Windows Advanced Local Procedure Call (ALPC), allowing low-privileged attackers to gain SYSTEM privileges. CVE-2026-81963 affects the Windows Update Stack due to improper link resolution and access controls, enabling similar privilege escalation. The September release also includes 974 Common Vulnerabilities and Exposures (CVEs) across various Microsoft products, with 723 affecting Windows. Users of Windows 11 24H2 and 25H2 receive updates via KB5124008, while Windows 11 26H1 receives KB5124012. Windows 11 24H2 Home or Pro editions will reach end of servicing on October 13, 2026. Users are advised to install the updates promptly and back up important data.