CVE Alert: CVE-2025-48004 – Microsoft – Windows 11 Version 25H2

Risk verdict

High risk of local privilege escalation on affected Windows builds; patching should be applied promptly.

Why this matters

A use-after-free in the Microsoft Brokering File System can let a local attacker elevate privileges without user interaction, enabling system compromise, persistence, and potential disabling of security controls. The impact is broad across desktop and server SKUs, increasing the chance of full device takeovers in biased environments or misconfigured networks.

Most likely attack path

An attacker with local access executes code that triggers the use-after-free, gaining elevated privileges (no user interaction required). With local access and a successful exploit, the adversary can reach high- or system-level access and pivot to other resources within the host, given the scope remains unchanged. Exploitability is constrained by the local vector and high impact on confidentiality, integrity, and availability.

Who is most exposed

Organizations with Windows 11 (25H2, 22H2, 23H2, 24H2) and Windows Server deployments are broadly affected, including ARM64 and x64 endpoints and server core installations. Environments with delayed patching or broad local admin use are at greater risk.

Detection ideas

• Kernel memory corruption indicators and related crash dumps (memory corruption/Use After Free signs).
• Unusual brokered file system activity or process creation with elevated privileges shortly after startup.
• Security logs showing unexpected privilege escalation attempts or anomalous SYS calls.
• EDR alerts for memory corruption patterns and anomalous service/process changes.

Mitigation and prioritisation

• Apply the latest vendor security updates for all affected Windows builds immediately.
• Enforce least privilege: reduce local admin accounts, limit brokered file system use, and tighten lateral movement controls.
• Enhance detection: enable ASR rules, kernel memory anomaly monitoring, and robust EDR coverage; review crash dumps for patterns.
• Verify patch deployment in staging before broad rollout; schedule coordination with Change Management.
• If KEV/EPSS indicators exist in your ecosystem, escalate to Priority 1; otherwise proceed with high-priority patching and controls.