Microsoft Windows Kerberos: Authentication bypass leading to privilege escalation

Summary

Windows Kerberos, the authentication component of Windows clients, servers and Active Directory domain controllers, contains an authentication bypass using an alternate path or channel (CWE-288). According to the CVE record, an unauthorized attacker on the network can elevate privileges, and the CVE is rated CVSS 9.8 (Critical) with no privileges or user interaction required. The record and rating are not yet confirmed by Microsoft's advisory or NVD analysis, so the exact conditions must be verified.

Affected

• Windows 10 Version 1607 (10.0.14393.0 to before 10.0.14393.9688)
• Windows 10 Version 1809 (10.0.17763.0 to before 10.0.17763.9487)
• Windows 10 Version 21H2 (10.0.19044.0 to before 10.0.19044.7846)
• Windows 10 Version 22H2 (10.0.19045.0 to before 10.0.19045.7846)
• Windows 11 Version 23H2 (10.0.22631.0 to before 10.0.22631.7711)
• Windows 11 Version 24H2 (10.0.26100.0 to before 10.0.26100.9974)
• Windows 11 Version 25H2 (10.0.26200.0 to before 10.0.26200.9974)
• Windows 11 Version 26H1 (10.0.28000.0 to before 10.0.28000.3501)
• Windows 11 Version 26H2 (10.0.26300.0 to before 10.0.26300.9974)
• Windows Server 2012 incl. Server Core (6.2.9200.0 to before 6.2.9200.26434)
• Windows Server 2012 R2 incl. Server Core (6.3.9600.0 to before 6.3.9600.23470)
• Windows Server 2016 (10.0.14393.0 to before 10.0.14393.9688)

Fixed in

• Fixed builds according to the CVE record: the first build at or above the upper bound of each affected range listed above.
• Corresponding KB numbers: Unknown. The KB numbers in secondary listings have not been verified against Microsoft's advisory.

Workaround

Unknown.

Exploitation

• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• No public proof of concept or CISA KEV entry was found for this CVE.
• Exploitation status in Microsoft's advisory: Unknown.

Our recommendation

• Open the Microsoft Security Update Guide entry and confirm the affected builds, fixed KB numbers and exploitation flags.
• Install the October or current cumulative update on all domain controllers and Windows servers as a priority, then on domain-joined clients.
• Prioritise domain controllers that are reachable from untrusted networks, including VPN and partner connections, and restrict that exposure.
• Monitor domain controller and Kerberos event logs for unusual authentication activity until patching is verified.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Microsoft Security Update Guide: CVE-2026-85844 msrc.microsoft.com
• Community listing of the October 2026 release (CVE-2026-85844 entry) community.absolute.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 10 Nov 2026, 20:36.