CVE-2026-20866 | Windows Management Services Elevation of Privilege Vulnerability

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Management Services allows an authorized attacker to elevate privileges locally.

Published: 2026-01-13 Last update: 2026-01-15 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-20866 is rated Low Risk (34.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.04%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-20866

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-14 — 0.04% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-20866

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.1 6.0 [email protected]

Weakness enumeration for CVE-2026-20866

Affected software / configurations for CVE-2026-20866

Vendor Product Version Raw CPE
microsoft windows_10_1809 < 10.0.17763.8276 cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
microsoft windows_10_1809 < 10.0.17763.8276 cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
microsoft windows_10_21h2 < 10.0.19044.6809 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*
microsoft windows_10_22h2 < 10.0.19045.6809 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*
microsoft windows_11_23h2 < 10.0.22631.6491 cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*
microsoft windows_11_24h2 < 10.0.26100.7623 cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*
microsoft windows_11_25h2 < 10.0.26200.7623 cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:*:*
microsoft windows_server_2019 < 10.0.17763.8276 cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
microsoft windows_server_2022 < 10.0.20348.4648 cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
microsoft windows_server_2022_23h2 < 10.0.25398.2092 cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
microsoft windows_server_2025 < 10.0.26100.32230 cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

References for CVE-2026-20866

cvelogic Threat Intelligence