CVE Alert: CVE-2025-55331 – Microsoft – Windows 11 Version 25H2

**Risk verdict** High. Local privilege escalation with system-wide impact poses a clear preescalation risk, and urgency hinges on whether active exploitation is observed (data not provided).

**Why this matters** The flaw enables an authenticated attacker with local access to elevate privileges, potentially yielding full control of affected hosts. In organisations with Windows endpoints and print infrastructure, an exploited host could be used as a foothold for lateral movement or deployment of follow-on payloads, compromising confidentiality, integrity and availability.

**Most likely attack path** The attack requires local access and low privileges, with no user interaction, exploiting a use-after-free in PrintWorkflowUserSvc. Once the attacker achieves code execution, they can obtain higher privileges (SYSTEM) and potentially impact connected systems or data. The feasibility is shaped by restricted preconditions (local, privilege-restricted); exploitation risk increases on endpoints with Print Spooler enabled and exposed print workflows.

**Who is most exposed** Endpoints and print servers in enterprise Windows environments, especially where Print Spooler services are active or exposed to users and automation, are most at risk. Systems deployed with multiple Windows versions listed in the affected set are particularly vulnerable.

Detection ideas

• Monitor for crashes or hangs of PrintWorkflowUserSvc and related memory-corruption indicators.
• Look for unusual process trees where a low-privilege process elevates to SYSTEM or spawns privileged tasks.
• Detect anomalous token manipulation or new elevated tokens around spooler-related processes.
• Inspect crash dumps or ETW traces indicating use-after-free conditions in print workflow components.
• Correlate spike in memory/CPU usage with service restarts or rapid privilege changes.

Mitigation and prioritisation

• Apply latest Windows updates for all affected versions; prioritise patching in test/production cycles.
• If unnecessary, disable or harden Print Spooler and PrintWorkflow components; enable least-privilege execution for the service.
• Enforce strict application control and monitor for suspicious service modifications or DLL loads related to print services.
• Review change-management logs for recent spooler-related adjustments; implement temporary compensating controls (network segmentation, restricted admin access).
• If KEV evidence or EPSS ≥ 0.5 is observed, treat as priority 1. If not, proceed with standard high-priority remediation and monitoring.