# CVE-2026-85806: Microsoft Network Policy Server integer underflow remote code execution

Source: https://junglewise.ai/threats/cve-2026-85806-integer-underflow-wrap-or-wraparound-in-network-policy-server-nps  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-85806 · Severity: critical · CVSS 9.8 · Published 2026-10-13

Network Policy Server (NPS) is a Windows service that authenticates and authorizes remote access connections. An integer underflow vulnerability allows an unauthenticated attacker to execute arbitrary code on affected servers over the network. This could lead to complete system compromise and unauthorized access to network resources.

Technologies: [Microsoft Network Policy Server](https://junglewise.ai/threats/technologies/network-policy-server). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-85806 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-85806 being exploited in the wild.

**How severe is CVE-2026-85806?** Critical severity, with a CVSS score of 9.8, published 13 October 2026.

**Which products and versions are affected?** Microsoft Network Policy Server.

**Is there a fix for CVE-2026-85806?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-85806 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-85806?** Check whether you run Microsoft Network Policy Server. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer underflow vulnerability exists in Windows Network Policy Server's packet processing logic. The vulnerability can be triggered remotely without authentication via network-accessible NPS services, allowing an attacker to execute arbitrary code with system privileges. No user interaction is required.

## Affected products

- Microsoft Network Policy Server

## Timeline

- 2026-10-13: advisory

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85806](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85806)

## Related threats

- [Microsoft Network Policy Server out-of-bounds read](https://junglewise.ai/threats/cve-2026-96246-out-of-bounds-read-in-network-policy-server-nps-allows-an)
- [Microsoft Network Policy Server use-after-free remote code execution](https://junglewise.ai/threats/cve-2026-85811-use-after-free-in-network-policy-server-nps-allows-an)
- [Microsoft Network Policy Server use-after-free remote code execution](https://junglewise.ai/threats/cve-2026-85799-use-after-free-in-network-policy-server-nps-allows-an)
- [Microsoft Network Policy Server use-after-free RCE](https://junglewise.ai/threats/cve-2026-85371-use-after-free-in-network-policy-server-nps-allows-an)
- [Microsoft Network Policy Server out-of-bounds read denial of service](https://junglewise.ai/threats/cve-2026-83655-out-of-bounds-read-in-network-policy-server-nps-allows-an)