Double Free in Microsoft Windows 11 23h2
CVE-2026-26166
Double free in Windows Shell allows an authorized attacker to elevate privileges locally.
Vulnerability class: Double Free
EPSS: 0.002 (15.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Microsoft Windows_11_23h2
- Microsoft Windows_11_24h2
- Microsoft Windows_11_25h2
- Microsoft Windows_11_26h1
- Microsoft Windows 11 Version 22h3 — versions 10.0.22631.0
- 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
Weakness classification (CWE)
References
- Windows Shell Elevation of Privilege Vulnerability (vendor-advisory, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-26166?
- CVE-2026-26166 is a high-severity vulnerability in Microsoft Windows 11 23h2, classified under Double Free. CVSS score: 7.0/10. Published 2026-04-14.
- How severe is CVE-2026-26166?
- High severity. CVSS v3 base score is 7.0 out of 10.