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PatchSiren cyber security CVE debrief

CVE-2026-85811 Microsoft CVE debrief

A use-after-free vulnerability in the Network Policy Server (NPS) allows an unauthorized attacker to execute code over an adjacent network. Multiple Windows versions and server releases are affected, including Windows 10, Windows 11, and Windows Server 2012 through 2025. This vulnerability has a high severity score and requires immediate attention from defenders responsible for these systems, especially those exposed to adjacent networks. The vulnerability exists due to improper handling of memory, allowing attackers to execute code remotely.

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-13
Original CVE updated
2026-10-13
Advisory published
2026-10-13
Advisory updated
2026-10-13

Who should care

Defenders responsible for Windows 10, Windows 11, and Windows Server systems, especially those exposed to adjacent networks, should assess exposure and prioritize patching.

Why it matters

CVE-2026-85811 is a high-severity vulnerability in Network Policy Server (NPS) that allows remote code execution. Defenders should prioritize patching affected systems, especially those exposed to adjacent networks, to prevent potential system compromise and data breaches.

  • Remote code execution over adjacent networks
  • Potential system compromise and data breaches
  • Necessity for immediate patching or mitigation
  • Potential for lateral movement within networks

Technical summary

The vulnerability exists in the Network Policy Server (NPS) and allows an attacker to execute code remotely over an adjacent network due to a use-after-free issue. This vulnerability affects multiple Windows versions and server releases, including Windows 10, Windows 11, and Windows Server 2012 through 2025. Defenders should prioritize patching affected systems, especially those exposed to adjacent networks, to prevent potential system compromise and data breaches.

Defensive priority

Defenders should prioritize patching affected systems, especially those exposed to adjacent networks.

Recommended defensive actions

  • Patch affected Windows 10, Windows 11, and Windows Server versions.
  • Isolate affected systems from adjacent networks if patching is not immediately feasible.
  • Monitor network traffic for suspicious activity.
  • Verify system configurations and inventory for affected versions.

Evidence notes

The CVE Program and NVD provide official records of the vulnerability. Microsoft has a supplemental advisory for the vulnerability. The vulnerability was publicly disclosed on October 13, 2026, and there have been no changes to the CVE record since then. Additional information can be found in the official CVE Program record and the NIST NVD vulnerability detail page.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-85811 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-85811

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-85811 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-85811

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental 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.