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MSRC compact vulnerability detail

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.

Severity
Important
Impact
Elevation of Privilege
CVSS
7.8 base · 6.8 temporal
Release
2026-01-13
Signals
Windows Management Services Elevation of Privilege Exploited: No Publicly disclosed: No Exploitability: Exploitation Less Likely
CWE
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Patch Diff
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Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Management Services allows an authorized attacker to elevate privileges locally.
FAQ / Articles
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.
FAQ
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to win a race condition.
FAQ
According to the CVSS metric, successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability? In this case, a successful attack could be performed from a low privilege AppContainer. The attacker could elevate their privileges and execute code or access resources at a higher integrity level than that of the AppContainer execution environment.
FAQ
What privileges could be gained by an attacker who successfully exploited the vulnerability? An attacker could use this vulnerability to elevate privileges from a Low Integrity Level in a contained ("sandboxed") execution environment to a Medium Integrity Level. Please refer to AppContainer isolation and Mandatory Integrity Control for more information.