Critical RCE flaw in Windows IKE Extension now actively exploited

A double-free memory-corruption flaw (CWE-415) in the Microsoft Windows Internet Key Exchange (IKE) service extension allows a remote, unauthenticated attacker to trigger the bug with crafted network traffic, with no privileges or user interaction required. Successful exploitation yields remote code execution with full system impact, reflected in the critical 9.8 CVSS score (high confidentiality, integrity, and availability). The vulnerable IKE component is present in Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (23H2, 24H2, 25H2, 26H1), and Windows Server 2016, 2019, and 2022 (including 23H2), which ship it as a built-in feature. CISA added the flaw to the Known Exploited Vulnerabilities catalog on 2026-08-18, and security reporting confirms it is being actively exploited in the wild, though ransomware use is not yet confirmed. No public proof-of-concept is known, but the high EPSS score (72.7%, 99th percentile) signals a very strong likelihood of imminent or ongoing exploitation.

Do: Apply Microsoft's security updates for CVE-2026-33824 to all affected Windows 10, Windows 11, and Windows Server releases, prioritizing internet-exposed systems where IKE/VPN is reachable (UDP 500/4500), per BOD 26-04 requirements. Organizations unable to patch promptly should restrict or discontinue use of exposed IKE/VPN services on affected hosts until updated. Triage VPN endpoints and remote-access servers for crashes or suspicious IKE traffic given confirmed in-the-wild exploitation.