Double free in Microsoft Windows and Windows Server - CVE-2026-103571
Published: November 10, 2026
Vulnerability identifier: #VU164616
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-103571
CWE-ID: CWE-415
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges to SYSTEM and run processes in an elevated context.
The vulnerability exists due to a double free in the Windows Cryptography Next Generation (CNG) Key Isolation service when managing memory. A local user can run a specially crafted application after gaining execution on the victim system to elevate privileges to SYSTEM.
Successful exploitation requires winning a race condition.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-103571
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7846, 10 22H2 10.0.19045.7846, 10 1607 10.0.14393.9688, 10 1809 10.0.17763.9487, 11 23H2 10.0.22631.7711, 11 24H2 10.0.26100.9911, 11 24H2 10.0.26100.9974, 11 25H2 10.0.26200.9911, 11 25H2 10.0.26200.9974, 11 26H1 10.0.28000.3501
Windows Server - addressed in versions 2016 10.0.14393.9688, 2019 10.0.17763.9487, 2022 10.0.20348.5870, 2025 10.0.26100.33730, 2025 10.0.26100.33822
Windows Server - addressed in versions 2016 10.0.14393.9688, 2019 10.0.17763.9487, 2022 10.0.20348.5870, 2025 10.0.26100.33730, 2025 10.0.26100.33822