CVE-2026-54121
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper authorization in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges over a network.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceImproper authorization in Active Directory Certificate Services (AD CS) allows an authenticated attacker to exploit insufficient access controls in the certificate enrollment process to elevate privileges over the network. This authorization bypass enables a user with basic domain credentials to obtain higher-privilege certificates or certificate templates that should be restricted to privileged users.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 10.0.14393.9339< 10.0.17763.9020all versions= r2< 10.0.14393.9339< 10.0.17763.9020< 10.0.20348.5386< 10.0.26100.33158CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify AD CS role is installedRun 'Get-WindowsFeature AD-Certificate' in PowerShell on the server, or check Services for 'Active Directory Certificate Services'Affected if AD CS role is present on the server
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Check Windows version against affected rangesRun 'winver' or 'systeminfo | findstr /B /C:"OS Version"' to obtain the build numberAffected if Version is lower than 10.0.14393.9339 (1607/2016), 10.0.17763.9020 (1809/2019), 10.0.20348.5386 (2022), or 10.0.26100.33158 (2025), or if running Windows Server 2012/R2
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Identify certificate templates with sensitive permissionsOpen 'certtmpl.msc', right-click each template, go to Security tab, and review which users or groups have 'Allow Enroll' or 'Allow Full Control' permissionsAffected if Standard domain users have enrollment rights on templates intended for administrators (such as 'Domain Controller', 'Smartcard Logon', 'SubCA', or 'Administrator' templates)
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Review enrollment agent and certificate request agent permissionsUse 'certutil -view -restrict "Disposition=20" -out "RequestID,RequesterName,CertificateTemplate"' or check template properties for 'Issuance Requirements' including authorized signatures and enrollment agent flagsAffected if Templates permit enrollment by low-privilege users without requiring authorized signatures or enrollment agent certificates
The environment is affected if the server runs a vulnerable Windows version with AD CS installed AND standard domain users can enroll in certificate templates that should be restricted to privileged users.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data10.0.14393.933910.0.17763.902010.0.20348.5386
Review and restrict AD CS certificate template permissions, enrollment rights, and access control lists (ACLs) following Microsoft's AD CS security best practices; implement proper authorization checks for certificate requests and restrict enrollment to authorized principals only.
- Consultation8.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,608.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-54121 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-54121 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data