Cyber Posture

CVE-2026-20918

High

Published: 13 January 2026

Published
13 January 2026
Modified
15 January 2026
KEV Added
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.0003 7.1th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-20918 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 SI-2 (Flaw Remediation) and AC-6 (Least Privilege).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Privilege Escalation (T1068). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Requires timely identification, reporting, and patching of the specific race condition flaw in Windows Management Services to prevent local privilege escalation.

prevent

Prevents unauthorized and unintended information transfer via shared system resources, directly addressing the improper synchronization in concurrent execution exploited by this CVE.

prevent

Enforces least privilege for processes, limiting the potential impact and success of privilege escalation resulting from the race condition vulnerability.

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Race condition in Windows Management Services directly enables local privilege escalation via exploitation of the vulnerability.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

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-2026-20918 is a race condition vulnerability stemming from concurrent execution using a shared resource with improper synchronization in Windows Management Services. Published on 2026-01-13, it has been assigned 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 associated with CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) and CWE-416.

The vulnerability can be exploited by an authorized local attacker with low privileges who has physical or logical access to the target system. Exploitation requires high attack complexity but no user interaction, allowing the attacker to change scope and achieve high impacts on confidentiality, integrity, and availability, ultimately enabling local privilege escalation.

Microsoft's advisory provides details and mitigation guidance in the update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20918.

Details

CWE(s)

Affected Products

microsoft
windows 10 1809
≤ 10.0.17763.8276 · ≤ 10.0.17763.8276
microsoft
windows 10 21h2
≤ 10.0.19044.6809
microsoft
windows 10 22h2
≤ 10.0.19045.6809
microsoft
windows 11 23h2
≤ 10.0.22631.6491
microsoft
windows 11 24h2
≤ 10.0.26100.7623
microsoft
windows 11 25h2
≤ 10.0.26200.7623
microsoft
windows server 2019
≤ 10.0.17763.8276
microsoft
windows server 2022
≤ 10.0.20348.4648
microsoft
windows server 2022 23h2
≤ 10.0.25398.2092
microsoft
windows server 2025
≤ 10.0.26100.32230

CVEs Like This One

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CVE-2026-32165Same product: Microsoft Windows 10 1809
CVE-2026-32158Same product: Microsoft Windows 10 1809
CVE-2026-32159Same product: Microsoft Windows 10 1809

References