CVE Alert: CVE-2025-54103 – Microsoft – Windows 10 Version 21H2

Risk verdict

High risk. Local privilege escalation with total impact is possible, and exploitation state is not clearly observed in current indicators.

Why this matters

An attacker with local access can elevate to SYSTEM, enabling persistence, full control of the host, and potential data access or disruption. The broad range of affected Windows versions across desktop and server surfaces means many devices could be exposed in enterprise environments.

Most likely attack path

Requires local access with no user interaction; the attacker triggers a use-after-free scenario in Windows Management Services to gain SYSTEM privileges. Once elevated, they can hijack critical services or processes, access protected memory/handles, and pursue further lateral movement using compromised credentials or misconfigurations.

Who is most exposed

Endpoints and servers running any of the affected Windows versions, particularly those with local admin rights or exposed management interfaces. Enterprise deployments with mixed versions or delayed patching are at greatest risk.

Detection ideas

• Unusual WMS process crashes or memory-related error reports.
• Privilege-escalation attempts to SYSTEM tokens or sudden token rotations.
• Unexplained service/process creation or termination around management services.
• Anomalous memory allocation/free patterns or crash dumps linked to management components.
• Correlated logins from hosts showing rapid escalation activity.

Mitigation and prioritisation

• Apply the latest security updates to all affected builds; verify patch deployment across devices and servers.
• Enforce least privilege, restrict local admin rights, and limit unauthorised local access.
• Enable EDR/monitoring for local privilege escalations and memory-corruption indicators; tighten ASR and Defender for Endpoint policies.
• Monitor and respond to anomalous WMS activity; ensure robust patch management windows.
• If KEV is confirmed or EPSS ≥ 0.5, treat as priority 1; data shows KEV/EPSS indications are uncertain, so plan accordingly. Consider a staged rollout with rollback if patching impacts critical services.