Junglewise Threat Intelligence

CVE-2026-20866: Microsoft Windows Management Services race condition privilege escalation

CVE-2026-20866 · Severity: high · CVSS 7.8 · Published 2026-01-13

Technologies: Microsoft Windows Server 2022, Microsoft Windows 10, Microsoft Windows Server 2019, Microsoft Windows 11. Vendors: Microsoft.

Executive brief

A security vulnerability exists in Windows Management Services, a core component used for managing and monitoring Windows systems. An attacker who already has basic access to a computer could exploit a timing flaw to gain full administrative control over the device. This could allow them to access sensitive data, install malicious software, or disrupt critical business operations.

Technical details

A race condition (CWE-362) exists in Windows Management Services due to improper synchronization during concurrent execution using a shared resource. The vulnerability requires an attacker to have local access and the ability to execute code with low privileges. By successfully exploiting the timing of specific operations, an attacker can achieve a privilege escalation, potentially reaching SYSTEM level. The attack complexity is rated as high, likely due to the precise timing required to win the race condition. Microsoft has released security updates to address this issue across affected Windows and Windows Server versions.

Affected products

  • Microsoft Windows 10 1809, 21H2, 22H2
  • Microsoft Windows 11 22H3, 23H2, 24H2, 25H2
  • Microsoft Windows Server 2019 All versions
  • Microsoft Windows Server 2022 All versions

Timeline

  • 2026-01-13: disclosed
  • 2026-01-13: patched

References

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