CVE-2026-45657
A use-after-free flaw in the Windows Kernel lets an unauthenticated attacker execute arbitrary code remotely over the network. The vulnerability affects multiple Windows 11 releases (23H2, 24H2, 25H2, 26H1) and Windows Server 2022 and 2025, and is rated critical with a CVSS score of 9.8. No public exploit or known exploitation in the wild has been reported.
No official fix yet. If none appears within 45 days of first tracking, this entry is removed automatically.
Who is affected
Users of Windows 11 versions 23H2, 24H2, 25H2, 26H1 and Windows Server 2022 or 2025.
Real-world impact
An attacker who can reach the system over the network could run code with the privileges of the affected system, potentially leading to full compromise.
Why this severity
The CVSS v3.1 base score of 9.8 (Critical) reflects that the flaw is network‑reachable, requires no authentication or user interaction, and can result in complete loss of confidentiality, integrity, and availability.
What to do about it
No official fix or mitigation is documented in the sources yet. Monitor the vendor advisory and apply the patch as soon as it is released.
No fix documented in sources
Timeline
- Jun 9, 2026 · Jun 9, 2026PublishedDisclosed and added to the National Vulnerability Database.
- Jul 23, 2026 · 12d agoAdvisory updatedThe NVD record was last revised.
How it’s attacked
References & advisories
- msrc.microsoft.com/update-guide/vulnerability/…vendor advisory