Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 26 Jun 2026.
Unifi Os ServerApplication · Ui

CVE-2026-34909

CRITICAL · 10.0 CVSS v3.1 Published 2026-05-22
Fix available
A fix is available. Upgrade to 5.0.8 / 5.1.12 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS Public exploit Remotely reachable No privileges Zero-click Patch available

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 · unedited
A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to access files on the underlying system that could be manipulated to access an underlying account.

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 confidence

Path Traversal vulnerability in UniFi OS devices allowing a network-adjacent attacker to escape directory restrictions and access sensitive files on the underlying filesystem, potentially enabling access to underlying system accounts.

MitigationApply vendor-provided patches/updates for UniFi OS when available; immediately restrict network exposure of UniFi management interfaces to trusted networks only.

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
Unifi Os ServerApplication
Affected:< 5.0.8
Unifi Cloud Gateway Industrial FirmwareOperating system
Affected:< 5.1.12
Unifi Dream Machine FirmwareOperating system
Affected:< 5.1.12
Unifi Dream Machine Pro FirmwareOperating system
Affected:< 5.1.12
Unifi Dream Machine Special Edition FirmwareOperating system
Affected:< 5.1.12
Unifi Dream Machine Pro Max FirmwareOperating system
Affected:< 5.1.12
Enterprise Fortress Gateway FirmwareOperating system
Affected:< 5.1.12
Unifi Dream Wall FirmwareOperating system
Affected:< 5.1.12

CVSS 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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify your UniFi OS device model
    Access the UniFi Controller or check the device itself to determine the exact model (e.g., UniFi Dream Machine, Dream Machine Pro, Cloud Gateway Industrial, etc.)
    Affected if The device model matches any of the affected products listed in the CVE
  2. Check the installed firmware version
    In the UniFi Controller UI, navigate to the device settings or use the ubiquiti-specific command to retrieve the current firmware version installed on the device
    Affected if The installed firmware version is below the threshold (less than 5.0.8 for UniFi OS Server, or less than 5.1.12 for all other listed devices)
  3. Verify the UniFi OS version if applicable
    For UniFi OS Server devices, determine the UniFi OS version rather than just the controller version, as the vulnerability affects the underlying OS
    Affected if The UniFi OS Server version is below 5.0.8
  4. Confirm network accessibility of management interface
    Determine if the UniFi management interface (typically ports 443/8080 or the specific UniFi OS web interface) is exposed to untrusted networks
    Affected if The management interface is accessible from untrusted network segments, which would allow an attacker to exploit the path traversal flaw

You are affected if your device is any of the listed UniFi OS products and the installed firmware version is below the specified thresholds (below 5.0.8 for UniFi OS Server, or below 5.1.12 for other models), and the management interface is network-accessible to potential attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 5.0.8 / 5.1.12 or later
Fixed in 5.0.85.1.12
Vendor patch community.ui.com →
Interim mitigation

Apply vendor-provided patches/updates for UniFi OS when available; immediately restrict network exposure of UniFi management interfaces to trusted networks only.

Recommended fix High confidence

Unifi OS Server: upgrade to 5.0.8 or later; Unifi Cloud Gateway Industrial/Dream Machine/Dream Machine Pro/Dream Machine SE/Dream Machine Pro Max/Enterprise Fortress Gateway/Dream Wall: upgrade to 5.1.12 or later

  1. 1. Identify your specific UniFi OS device model from the affected product list
  2. 2. Access the UniFi OS console interface for your device
  3. 3. Navigate to Settings > System > Firmware to check the current installed version
  4. 4. Download the latest firmware for your device from the official Ubiquiti Downloads page (https://www.ui.com/download/unifi)
  5. 5. In the UniFi OS interface, upload the firmware file and initiate the update
  6. 6. Wait for the device to reboot and apply the update
  7. 7. Verify the firmware version has been updated to the fixed release
Caveat Review Ubiquiti release notes for any configuration or feature changes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Unifi Os Server Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,780
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,448.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-34909 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34909 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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