CVE-2026-54121
Active Directory Certificate Services Elevation of Privilege Vulnerability
No known exploitation. EPSS puts it in the 55th percentile. Fixed versions are out.
What to do
Find your product and version, then upgrade to the build on the right.
- Microsoft Windows 10 Version 1607Affected: ≥ 10.0.14393.0, < 10.0.14393.9339Upgrade to: 10.0.14393.9339Affected: ≥ 10.0.17763.0, < 10.0.17763.9020Upgrade to: 10.0.17763.9020Stated by: CVE record
- Microsoft Windows Server 2016Affected: ≥ 10.0.14393.0, < 10.0.14393.9339Upgrade to: 10.0.14393.9339Stated by: CVE record
- Microsoft Windows Server 2019Affected: ≥ 10.0.17763.0, < 10.0.17763.9020Upgrade to: 10.0.17763.9020Stated by: CVE record
- Microsoft Windows Server 2022Affected: ≥ 10.0.20348.0, < 10.0.20348.5386Upgrade to: 10.0.20348.5386Stated by: CVE record
- Microsoft Windows Server 2025Affected: ≥ 10.0.26100.0, < 10.0.26100.33158Upgrade to: 10.0.26100.33158Stated by: CVE record
Versions as the sources state them. 2 more products have version data. Full version matrix after sign-in
Coverage timeline
4 publishersResearchers analyzed CVE-2026-54121 ('Certighost'), a privilege escalation flaw in AD CS, for which a public PoC exists; Microsoft patched the issue in July 2026, though no in-the-wild exploitation was confirmed at disclosure.
A proof-of-concept exploit was released for a patched flaw in Microsoft Active Directory Certificate Services allowing low-privileged users to impersonate domain controllers.
Sourced from public security reporting — each date is when it was published, not when it happened. 5 further articles named this CVE in wider roundups without reporting it as a distinct event.
What it is
From the CVE record
Improper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.8% chance of exploitation activity in the next 30 days, which ranks it in the 55th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
9 events over 13 days, from the signal feeds we watch.
- Analysis publishedCertighost: how one domain account turns AD CS into a Domain Controller (CVE-2026-54121)
- Patch availablerecord updated
- OpenVAS check added
- Record updated
- Publishedweakness classified, record updated, record updated
Affected products
- Windows 10 Version 1607Operating Systems / windows
- Windows Server 2012 (Server Core installation)Operating Systems / windows
- Windows Server 2016 (Server Core installation)Operating Systems / windows
- Windows Server 2019 (Server Core installation)Operating Systems / windows
- Windows Server 2022Operating Systems / windows
- Windows Server 2025 (Server Core installation)Operating Systems / windows
- Windows Server 2012 R2 (Server Core installation)Operating Systems / windows
And 13 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Scored 8.8 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required LowRequires basic user-level privileges
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
References in the record
Analysis on the cve.tools blog
In the news
All news- Certighost and the Privilege Hiding in Your Certificate Authority
- Week in review: Claude breached three companies during tests, AD CS domain-takeover PoC released
- 'Certighost' Flaw Haunts Microsoft Active Directory Certificates
- New Certighost PoC exploit lets attackers hijack Windows domains
- ⚡ Weekly Recap: Rogue AI Agents, Check Point Exploit, Slopsquatting, ClickFix Lures and More
- PoC exploit released for critical AD CS domain-takeover flaw (CVE-2026-54121)
- Certighost Exploit Lets Low-Privileged Active Directory Users Impersonate a Domain Controller
- Microsoft and Adobe Patch Tuesday, July 2026 Security Update Review
- Microsoft Patch Tuesday for July 2026 — Snort rules and prominent vulnerabilities
- Microsoft Patch Tuesday July 2026 - The AI Acopolypse is Here
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