CVE Alert: CVE-2025-55335 – Microsoft – Windows 10 Version 1809

Risk verdict

High risk of local privilege escalation; patch promptly for affected Windows versions.

Why this matters

An attacker who can run code on an vulnerable host could use the NTFS use-after-free flaw to elevate to SYSTEM, enabling full control, credential access, and persistence. The impact is local, but the resulting compromise can enable broader enterprise access and data exposure if multiple hosts are affected or central services are reachable.

Most likely attack path

Exploitation requires local access with no user interaction and no privileges required, but high complexity to trigger the condition. A foothold on a machine (malware, removable media, or compromised admin workflow) could abuse NTFS operations to gain SYSTEM, then pivot to sensitive assets or create persistence. Lateral movement would depend on subsequent credential access and network reach.

Who is most exposed

Endpoints and servers running the affected Windows variants, including client desktops and Server editions in mixed environments, are most at risk, particularly where patch cadence is slower or devices remain on older builds.

Detection ideas

• Kernel crashes or memory-corruption indicators in NTFS drivers; collect crash dumps for ntfs.sys.
• Unusual or failed NTFS operations followed by rapid privilege changes or process spawning at SYSTEM level.
• New or unexpected SYSTEM-level processes, services, or scheduled tasks shortly after NTFS activity.
• Anomalous security agent or EDR alerts tied to kernel-mode abuse or privilege escalation attempts.
• Post-exploitation LPE patterns: credential access attempts, unusual NTLM/kerberos activity.

Mitigation and prioritisation

• Apply the vendor-supplied patches to all affected builds (Windows 10 1809, Server 2019, 2022, 2025 and related editions).
• Verify patch deployment via patch management tooling; reboot as required.
• Strengthen defence-in-depth: restrict local account usage, enforce least-privilege, enable memory integrity/ASLR, and harden NTFS access controls.
• Monitor and alert on kernel-mode anomalies and SYSTEM-level process creation; prioritise patch rollout in high-risk environments.
• Plan a rapid patch window with testing in a non-production cohort before full organisation-wide deployment.