CVE-2026-85865: Windows DHCP Server improper authentication security feature bypass

CVE-2026-85865 · Severity: medium · CVSS 5.5 · Published 2026-10-13

Windows DHCP Server, which manages automatic IP address assignment on corporate networks, contains an authentication flaw that allows an authorized local user to bypass a security feature. An attacker with local access could circumvent network security controls, potentially leading to unauthorized network access or configuration changes.

Technologies: Microsoft Windows DHCP Server, Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022, Microsoft Windows Server 2025. Vendors: Microsoft.

Quick answers

Is CVE-2026-85865 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-85865 being exploited in the wild.
How severe is CVE-2026-85865?
Medium severity, with a CVSS score of 5.5, published 13 October 2026.
Which products and versions are affected?
Microsoft Windows DHCP Server.
Is there a fix for CVE-2026-85865?
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-2026-85865 attacked?
It is attacked with local access.
Am I affected by CVE-2026-85865?
Check whether you run Microsoft Windows DHCP Server, Microsoft Windows 10 1607, Microsoft Windows 10 1809 or one of the others listed. 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 improper authentication vulnerability in Windows DHCP Server allows a locally authenticated attacker to bypass a security feature. The attack requires existing local access to the system and does not affect remote attackers. A security update from Microsoft addresses this authentication bypass.

Affected products

  • Microsoft Windows DHCP Server

Timeline

  • 2026-10-13: disclosed

References

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