CVE-2026-55116 in UniFi OS Devices
A 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.
Quick answer
Ubiquiti UniFi OS devices should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- Dream Machines before UniFi OS 5.1.19
- Enterprise Fortress Gateway before UniFi OS 5.1.19
- Dream Wall before UniFi OS 5.1.19
- Dream Routers before UniFi OS 5.1.19
- Express 7 before UniFi OS 5.1.19
- Cloud Gateways before UniFi OS 5.1.19
- Enterprise Firewall Core before UniFi OS 5.1.19
Fixed versions
- UniFi OS 5.1.19 or later for affected device families
How to fix it
CVE-2026-55116 affects UniFi OS devices. The issue means some network setups may allow unauthorized changes to UniFi OS devices. Treat this as a priority if the system is reachable by users, tenants, or the network. Update to UniFi OS 5.1.19 or later, or follow the vendor advisory if your branch needs a backport.
- Inventory every UniFi OS devices instance, appliance, container, or package in use.
- Compare installed versions with the affected ranges in the vendor advisory.
- Update to UniFi OS 5.1.19 or later on supported systems.
- If you cannot update today, restrict access to trusted admins and trusted networks only.
- Review logs for unusual access, privilege changes, file access, or failed requests.
- Rotate secrets, tokens, and service accounts if exposure or abuse is suspected.
- Document the change and keep the advisory link with the ticket.
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Verify the fix
- Confirm the installed version is UniFi OS 5.1.19 or later.
- Confirm exposed admin, API, SFTP, or device access is limited to trusted users.
- Retest the affected workflow after the update or mitigation.
- Review logs again after patching for repeated suspicious activity.
- Run a new Fixnx scan where the affected service is part of the public site.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-55116?
Ubiquiti UniFi OS devices versions listed as affected should be reviewed: Dream Machines before UniFi OS 5.1.19, Enterprise Fortress Gateway before UniFi OS 5.1.19, Dream Wall before UniFi OS 5.1.19, Dream Routers before UniFi OS 5.1.19, Express 7 before UniFi OS 5.1.19, Cloud Gateways before UniFi OS 5.1.19, Enterprise Firewall Core before UniFi OS 5.1.19.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.