What is CVE-2026-62815?

CVE-2026-62815 is a critical-severity vulnerability in Microsoft Windows 11 Version 23h2, classified under Use After Free. CVSS score: 9.8/10. Published 2026-08-11.

How severe is CVE-2026-62815?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Use After Free in Microsoft Windows 11 Version 23h2

CVE-2026-62815

Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.

Vulnerability class: Use-After-Free

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Microsoft Windows 11 Version 23h2 — versions 10.0.22631.0
Microsoft Windows 11 Version 24h2 — versions 10.0.26100.0
Microsoft Windows 11 Version 25h2 — versions 10.0.26200.0
Microsoft Windows 11 Version 26h1 — versions 10.0.28000.0
Microsoft Windows Server 2022 — versions 10.0.20348.0
Microsoft Windows Server 2025 — versions 10.0.26100.0
Microsoft Windows Server 2025 (Server Core Installation) — versions 10.0.26100.0

Weakness classification (CWE)

CWE-416 — Use After Free

References

secure@microsoft.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-62815?: CVE-2026-62815 is a critical-severity vulnerability in Microsoft Windows 11 Version 23h2, classified under Use After Free. CVSS score: 9.8/10. Published 2026-08-11.
How severe is CVE-2026-62815?: Critical severity. CVSS v3 base score is 9.8 out of 10.