Missing authentication for critical function in Windows Credential Guard allows an authorized attacker to perform spoofing locally.
Fix
Microsoft's update · Important
- KB5127648 — Windows 11 Version 26H2 · build 10.0.26300.9711 · restart required
- KB5126651 — Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809, Windows Server 2019, Windows Server 2019 (Server Core installation) · build 10.0.17763.9376 · restart required
- KB5126655 — Windows Server 2022, Windows Server 2022 (Server Core installation) · build 10.0.20348.5761 · restart required
- KB5126657 — Windows 10 Version 21H2 for 32-bit Systems, Windows 10 Version 21H2 · build 10.0.19044.7807 · restart required
- KB5126657 — Windows 10 Version 22H2, Windows 10 Version 22H2 for 32-bit Systems · build 10.0.19045.7807 · restart required
- KB5126646 — Windows Server 2025 (Server Core installation), Windows Server 2025 · build 10.0.26100.33650 · restart required
- KB5127648 — Windows 11 Version 25H2 · build 10.0.26200.9711 · restart required
- KB5126653 — Windows 11 Version 23H2 · build 10.0.22631.7652 · restart required
- KB5127648 — Windows 11 Version 24H2 · build 10.0.26100.9711 · restart required
- KB5127646 — Windows 11 version 26H1, Windows 11 Version 26H1 · build 10.0.28000.3231 · restart required
From the 2026-Oct release note of Microsoft's Security Update Guide, revised 2026-10-28 · Exploitation Less Likely.
Patch, vendor advisory and mitigation references on NVD 1
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70580 Patch, Vendor Advisory
STIG rules that mitigate this class
Credential Guard isolates NTLM hashes and Kerberos tickets from the LSASS process the class of flaw reads. Microsoft Learn, "Credential Guard overview" (the owner's mapping, data/mitigations.yaml: credential-guard)
- WN11-CC-000075 CAT I Credential Guard must be running on Windows 11 systems. Microsoft Windows 11
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 5
- Cpes+21 CPE criteria (now 21)NVD modified 2026-10-28 17:46
- StatusPublished → AnalyzedNVD modified 2026-10-28 17:46
- CVSS8.8 (v3.1, CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) → 7.8 (v3.1, CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)NVD modified 2026-10-28 17:46
- StatusAwaiting Analysis → PublishedNVD modified 2026-10-19 19:32
- First seenCVSS 8.8NVD modified 2026-10-13 19:29
Affected (CPE criteria) 21
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:*cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:*cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:arm64:*cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:*cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*
References 1
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70580 Patch, Vendor Advisory