CVE-2026-55116
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 under certain network configurations could exploit an Improper Access Control vulnerability found in certain devices running UniFi OS to make unauthorized changes to such UniFi OS devices.
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 Access Control vulnerability in UniFi OS devices allows a network-adjacent attacker under specific network configurations to make unauthorized changes to the device. The flaw likely involves insufficient authentication or authorization checks for certain administrative functions accessible over the network.
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< 3.4.20CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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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Identify if UniFi Connect is installedLocate the UniFi Connect application on your UniFi OS device or controller. This may be visible in the device dashboard, application list, or system information panel.Affected if UniFi Connect is present on the system
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Determine the installed UniFi Connect versionAccess the UniFi Connect settings or application info panel to view the current software version number. This is typically found in the About or Version section of the UniFi Connect interface.Affected if The displayed version number is lower than 3.4.20 (e.g., 3.4.19, 3.4.15, etc.)
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Verify network accessibility of UniFi management interfacesCheck your network configuration to determine if UniFi device management ports (commonly 443, 8080, or device-specific ports) are accessible from network segments that contain untrusted or external systems.Affected if Management interfaces are exposed to network segments beyond your trusted internal network
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Confirm network adjacency exposureReview firewall rules, VLAN configurations, and access control lists to determine if an attacker on the same network segment or an adjacent segment could reach UniFi device configuration interfaces without authentication.Affected if UniFi management interfaces are reachable from network segments without proper network isolation or authentication barriers
You are affected if UniFi Connect version is below 3.4.20 AND the management interface is accessible from an untrusted or adjacent network segment.
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 · scoped3.4.20
Restrict network access to UniFi OS devices using firewall rules and network segmentation; disable unnecessary network-exposed services; monitor for unauthorized administrative actions; contact Ubiquiti for specific patch information.
UniFi Connect version 3.4.20 or later
- 1. Log into the UniFi Connect dashboard or access the UniFi OS console
- 2. Navigate to the system settings or software update section
- 3. Check the current UniFi Connect version installed
- 4. If the version is below 3.4.20, initiate an upgrade to version 3.4.20 or the latest available stable release
- 5. Verify the upgrade completed successfully and confirm the new version number
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55116 — 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-2026-55116 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
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