CVE-2026-54400
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 · uneditedA malicious actor with access to the network and high privileges could exploit an Improper Access Control vulnerability found in UniFi Access Application to escalate privileges on the host device.
In the news
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- Ubiquiti warns of new max severity UniFi OS vulnerability
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 confidenceThis is an Improper Access Control vulnerability in Ubiquiti's UniFi Access Application that allows a malicious actor with network access and existing high privileges to perform privilege escalation on the host device. The vulnerability has a critical CVSS score of 9.1, indicating severe potential impact from successful exploitation.
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< 4.2.29CVSS 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
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/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 UniFi Access Application is installedLocate the UniFi Access Application on the host system. Check installed programs or services list for 'UniFi Access' or 'UBi Access' software.Affected if UniFi Access Application is present on the system
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Check installed version numberIdentify the installed version of the UniFi Access Application through the software's about page, installed programs list, or system registry. Compare the version against the affected range: any version below 4.2.29 is vulnerable.Affected if Installed version is lower than 4.2.29
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Confirm network exposureDetermine if the UniFi Access Application management interface or API is accessible from the network. Check firewall rules, port listeners, and network service bindings for ports used by UniFi Access.Affected if Application is accessible over the network to untrusted users
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Assess account privilege levelReview the privileges of the account from which the check is being performed. Determine if the account has elevated or administrative privileges within the UniFi Access system.Affected if Current account has high/administrative privileges and network access is exposed
User is affected if UniFi Access Application version is below 4.2.29 AND the application is network-accessible AND the attacker already possesses high-privilege credentials.
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.
dbcve · scoped4.2.29
Apply available patches or updates for UniFi Access Application immediately. Until a patch is available, restrict network access to the application and follow the principle of least privilege for user accounts.
UniFi Access Application version 4.2.29 or later
- Access the UniFi Access Controller or UniFi Network Application management interface
- Navigate to the system settings or applications section
- Check the current version of UniFi Access Application
- Update UniFi Access Application to version 4.2.29 or later through the built-in update mechanism
- Alternatively, download the latest UniFi Access Application from the official Ubiquiti downloads page and reinstall
- After upgrading, verify the new version is running: 4.2.29 or higher
- Restart the UniFi Access Application service if not automatically restarted
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,440.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-54400 — 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-2026-54400 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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