Advisoriesby IbisMicrosoftCVE-2026-55001
Microsoft Windows Active Directory: improper certificate validation
Fix: upgrade to 10.0.14393.9339 or later (4 fixed versions below)
Improper certificate validation in Windows Active Directory allows an authorized attacker to elevate privileges locally.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| Windows 10 Version 1607 Product | >= 10.0.14393.0, < 10.0.14393.9339 | 10.0.14393.9339 |
| Windows 10 Version 1809 Product | >= 10.0.17763.0, < 10.0.17763.9020 | 10.0.17763.9020 |
| Windows Server 2016 Product | >= 10.0.14393.0, < 10.0.14393.9339 | 10.0.14393.9339 |
| Windows Server 2016 (Server Core installation) Product | >= 10.0.14393.0, < 10.0.14393.9339 | 10.0.14393.9339 |
| Windows Server 2019 Product | >= 10.0.17763.0, < 10.0.17763.9020 | 10.0.17763.9020 |
| Windows Server 2019 (Server Core installation) Product | >= 10.0.17763.0, < 10.0.17763.9020 | 10.0.17763.9020 |
| Windows Server 2022 Product | >= 10.0.20348.0, < 10.0.20348.5386 | 10.0.20348.5386 |
| Windows Server 2025 Product | >= 10.0.26100.0, < 10.0.26100.33158 | 10.0.26100.33158 |
| Windows Server 2025 (Server Core installation) Product | >= 10.0.26100.0, < 10.0.26100.33158 | 10.0.26100.33158 |
Details and references
- CVSS 3.1
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Severity from
- the vendor (its own CVE record or advisory)
- Weakness
- CWE-295