# CVE-2026-100222: Microsoft Network Policy Server heap overflow

Source: https://junglewise.ai/threats/cve-2026-100222-heap-based-buffer-overflow-in-network-policy-server-nps-allows  
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-2026-100222 · Severity: critical · CVSS 9.8 · Published 2026-10-13

Network Policy Server (NPS) is a Microsoft authentication and authorization system used to validate user credentials and enforce network access policies. A heap-based buffer overflow vulnerability allows remote attackers to execute arbitrary code on the server without authentication, potentially compromising network security and enabling data theft or lateral movement within an organization.

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-2026-100222 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100222 being exploited in the wild.

**How severe is CVE-2026-100222?** Critical severity, with a CVSS score of 9.8, published 13 October 2026.

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

**Is there a fix for CVE-2026-100222?** 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-2026-100222 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-100222?** Check whether you run Microsoft Network Policy Server at an affected version. 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

A heap-based buffer overflow in Microsoft Network Policy Server permits remote code execution without prior authentication. The vulnerability is triggered via a network vector, requiring only network connectivity to the NPS service. Successful exploitation grants an attacker arbitrary code execution in the context of the NPS process.

## Affected products

- Microsoft Network Policy Server <UNKNOWN>

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-100222](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-100222)

## 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 integer underflow remote code execution](https://junglewise.ai/threats/cve-2026-85806-integer-underflow-wrap-or-wraparound-in-network-policy-server-nps)
- [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)