CVE-2026-27917 Microsoft CVE debrief

Who should care

System administrators and security teams responsible for Windows 10, Windows 11, and Windows Server deployments should assess exposure and apply patches.

Why it matters

CVE-2026-27917 is a high-severity elevation of privilege vulnerability in the Windows WFP NDIS Lightweight Filter Driver (wfplwfs.sys). An authorized attacker can exploit this vulnerability locally to gain elevated privileges. System administrators and security teams should assess exposure and apply patches immediately for affected Windows 10, Windows 11, and Windows Server versions.

• Local elevation of privilege possible for authorized attackers
• Potential for lateral movement and further exploitation
• Requires patching of multiple Windows versions and editions
• Verification of system configurations and logs recommended

Technical summary

The Windows WFP NDIS Lightweight Filter Driver (wfplwfs.sys) is vulnerable to a use-after-free elevation of privilege issue. An authorized attacker can exploit this vulnerability locally to gain elevated privileges. The vulnerability is caused by a use-after-free issue in the Windows WFP NDIS Lightweight Filter Driver. Microsoft has released a patch for this issue, and users should apply it as soon as possible to prevent potential exploitation. The vulnerability affects Windows 10, Windows 11, and Windows Server versions.

Defensive priority

Apply patches immediately for Windows 10, Windows 11, and Windows Server versions listed in the affected products.

Recommended defensive actions

• Apply patches for affected Windows 10, Windows 11, and Windows Server versions
• Review system configurations for potential exposure
• Monitor system logs for suspicious activity

Evidence notes

The CVE Program and NVD provide official details on this vulnerability. Microsoft has released a patch for this issue. The vulnerability has been publicly disclosed and is considered high-severity. There is no evidence of public exploitation, but users should apply patches as soon as possible. The CVE record was published on 2026-04-14T16:57:12.195Z and has not been modified since then. The NVD entry is currently HIGH. The vulnerability affects multiple Windows versions and editions,

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.