CVE-2026-20867
Published: 13 January 2026
Summary
CVE-2026-20867 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-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the race condition vulnerability by requiring timely application of vendor patches for Windows Management Services as specified in Microsoft's advisory.
Prevents unauthorized and unintended information transfer via shared system resources, directly countering the improper synchronization causing the race condition.
Implements memory protections that mitigate exploitation of race conditions leading to double free and use-after-free issues in the affected component.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local race condition/use-after-free in Windows Management Services directly enables local privilege escalation (T1068).
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-2026-20867 is a race condition vulnerability arising from concurrent execution using a shared resource with improper synchronization in Windows Management Services. 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), 415 (double free), and 416 (use after free). The flaw affects Windows systems where the management services component fails to properly synchronize access to shared resources.
A local attacker with low privileges (PR:L) can exploit this vulnerability by racing to manipulate the shared resource during concurrent operations. The attack demands local access (AV:L) and high complexity (AC:H) but requires no user interaction (UI:N). Successful exploitation enables privilege escalation, with high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), amplified by a scope change to other privileges (S:C).
Microsoft's advisory on the MSRC update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20867 provides details on mitigation, including available patches for affected Windows versions. Security practitioners should review the guide for specific update instructions and apply them promptly to prevent local privilege escalation.
Details
- CWE(s)