CVE-2026-54401 in UniFi OS Server
A malicious actor with access to the network and low privileges could exploit a Server-Side Request Forgery (SSRF) to escalate privileges within such UniFi OS devices or instances.
Quick answer
Ubiquiti UniFi OS Server and 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
- UniFi OS Server and affected UniFi OS device families before 5.1.19
Fixed versions
- UniFi OS 5.1.19 or later for affected device families
How to fix it
CVE-2026-54401 affects UniFi OS Server and devices. The issue means a low-privilege network user may use SSRF to escalate privileges. Treat it as urgent if the system is reachable by users, browsers, admins, or the network. Update to UniFi OS 5.1.19 or later, or follow the vendor advisory if your branch needs a supported backport.
- Inventory every UniFi OS Server and devices install, device, browser fleet, 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, limit access to trusted users and trusted networks only.
- Review logs for unusual access, crashes, privilege changes, commands, or failed requests.
- Rotate secrets, tokens, and service accounts if abuse or data access is suspected.
- Document the patch and keep the advisory link with the change record.
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Verify the fix
- Confirm the installed version is UniFi OS 5.1.19 or later.
- Confirm exposed admin, API, browser, 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-2026-54401?
Ubiquiti UniFi OS Server and devices versions listed as affected should be reviewed: UniFi OS Server and affected UniFi OS device families before 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.