CVE-2026-20861
Published: 13 January 2026
Summary
CVE-2026-20861 is a high-severity Race Condition (CWE-362) vulnerability in Microsoft Windows 10 1809. 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 7.1th 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-16 (Memory Protection).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the race condition vulnerability in Windows Management Services by requiring timely application of vendor patches to remediate the flaw.
Prevents unauthorized information transfer via shared system resources, directly addressing the improper synchronization causing the race condition.
Provides memory protection safeguards against exploitation of double free and use-after-free issues triggered by the race condition in Windows Management Services.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Race condition (CWE-362) with UAF/double-free in Windows Management Services directly enables local privilege escalation (AV:L, PR:L) via exploitation of OS weakness.
NVD Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Management Services allows an authorized attacker to elevate privileges locally.
Deeper analysisAI
CVE-2026-20861 is a race condition vulnerability in Windows Management Services, arising from concurrent execution using a shared resource with improper synchronization. Published on 2026-01-13, 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 is linked to CWEs-362 (race condition), CWE-415 (double free), and CWE-416 (use after free). The flaw enables an authorized attacker to elevate privileges locally.
A local attacker with low privileges (PR:L) can exploit this vulnerability, though it requires high attack complexity (AC:H) and no user interaction (UI:N). Exploitation occurs in a local attack vector (AV:L) and results in a scope change (S:C), allowing high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H). This facilitates local privilege escalation for the attacker.
Microsoft's update guide provides details on mitigation, available at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20861.
Details
- CWE(s)