CVE-2026-54121Windows 10 1607 Vulnerability
Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.
Published Jul 14, 2026 · Updated Oct 8, 2026
Key Facts
Patch in the next maintenance window- CVE-2026-54121 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Windows 10 1607 (Microsoft), Windows 10 1809 (Microsoft), Windows Server 2012 (Microsoft) and 12 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 0.8% probability of exploitation in the next 30 days.
- Fixed versions are available, including Windows 10 1607 10.0.14393.9339, Windows 10 1809 10.0.17763.9020, Windows Server 2012 6.2.9200.26226.
- Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
Scores
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
EPSS (30-day exploit likelihood)
0.8%
Higher than 55.0% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
45/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
10
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisoryJVN JVNDB-2026-032925
Description
Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.
Affected Products
36 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 10 1607Microsoft | 10.0.14393.9339 | 10.0.14393.9339 |
| Windows 10 1809Microsoft | 10.0.17763.9020 | 10.0.17763.9020 |
| Windows Server 2012Microsoft | 6.2.9200.26226, r2, >= 6.2.9200.0 | 6.2.9200.26226 |
| windows server 2012 R2Microsoft | 6.3.9600.23291, >= 6.3.9600.0 | 6.3.9600.23291 |
| Windows Server 2016Microsoft | 10.0.14393.9339, >= 10.0.14393.0 | 10.0.14393.9339 |
Patched Releases
Windows 10 1607
10.0.14393.9339
Windows 10 1809
10.0.17763.9020
Windows Server 2012
6.2.9200.26226
windows server 2012 R2
6.3.9600.23291
Windows Server 2016
10.0.14393.9339
Windows Server 2019
10.0.17763.9020
Windows Server 2022
10.0.20348.5386
Windows Server 2025
10.0.26100.33158
Windows 10 Version 1607
10.0.14393.9339
Windows 10 Version 1809
10.0.17763.9020
Windows Server 2012 (Server Core installation)
6.2.9200.26226
Windows Server 2012 R2 (Server Core installation)
6.3.9600.23291
Windows Server 2016 (Server Core installation)
10.0.14393.9339
Windows Server 2019 (Server Core installation)
10.0.17763.9020
Windows Server 2025 (Server Core installation)
10.0.26100.33158
Timeline
Publicly disclosed
Jul 14, 2026
Last updated
Oct 8, 2026
Weakness Type
- CWE-285 Improper Authorization
FAQ
Common Questions.
Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.
Affected: Windows 10 1607 (Microsoft) versions 10.0.14393.9339; Windows 10 1809 (Microsoft) versions 10.0.17763.9020; Windows Server 2012 (Microsoft) versions 6.2.9200.26226, r2, >= 6.2.9200.0, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Windows 10 1607 10.0.14393.9339, Windows 10 1809 10.0.17763.9020, Windows Server 2012 6.2.9200.26226.
Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
Is CVE-2026-54121 On Your Attack Surface?
Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.
Request A Demo