CVE-2026-21231
Published: 10 February 2026
Summary
CVE-2026-21231 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 9.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-4 (Information in Shared System Resources) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-21231 is a race condition vulnerability (CWE-362) stemming from concurrent execution using a shared resource with improper synchronization in the Windows Kernel. This flaw enables an authorized local attacker to elevate privileges. It carries a CVSS v3.1 base score of 7.8 (AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H) and was published on 2026-02-10.
The vulnerability can be exploited by an attacker with low privileges (PR:L) who has local access to the system. Exploitation requires high attack complexity (AC:H) due to the race condition nature but needs no user interaction (UI:N). Successful exploitation changes scope (S:C) and grants high impacts across confidentiality, integrity, and availability (C:H/I:H/A:H), allowing the attacker to elevate to higher privileges on the affected Windows system.
For mitigation details, refer to the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21231.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-7312
Vulnerability details
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Kernel allows an authorized attacker to elevate privileges locally.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel race condition enabling privilege escalation by low-privileged local attacker directly matches Exploitation for Privilege Escalation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the specific race condition vulnerability in the Windows Kernel through timely application of vendor patches.
Prevents unauthorized information transfer via shared kernel resources exploited by the improper synchronization race condition.
Enforces least privilege for local low-privilege accounts, limiting the attack surface and impact of privilege escalation via the race condition.