dbcve.org
Airmax Ac FirmwareOperating system · Ui

CVE-2026-21639

HIGH · 8.8 CVSS v3.1 Published 2026-01-08
Fix available
A fix is available. Upgrade to 1.2.3 / 2.6.8 or later.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

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 in Wi-Fi range of the affected product could leverage a vulnerability in the airMAX Wireless Protocol to achieve a remote code execution (RCE) within the affected product.

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

A vulnerability in the airMAX Wireless Protocol allows an attacker within Wi-Fi range to achieve remote code execution on affected Ubiquiti products. The issue is in the proprietary wireless protocol used by airMAX devices.

MitigationRestrict physical/wireless access to affected devices, apply vendor firmware updates when available, and monitor for unauthorized wireless clients in proximity.

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
Airmax Ac FirmwareOperating system
Affected:< 8.7.21
Airmax M FirmwareOperating system
Affected:< 6.3.24
Airfiber Af60 Xg FirmwareOperating system
Affected:< 1.2.3
Airfiber Af60 FirmwareOperating system
Affected:< 2.6.8

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/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 checks

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

  1. Identify the device model
    Access the device web UI (typically http://192.168.1.1) and check the Device Overview page, or run 'show device-info' via SSH/Telnet to the device
    Affected if The device is a Ubiquiti airMAX AC, airMAX M, airFiber AF60-XG, or airFiber AF60 model
  2. Determine the installed firmware version
    In the web UI, go to System > Firmware or check the main status page for the firmware version number. Alternatively, run 'show version' via CLI
    Affected if The firmware version is below 8.7.21 for airMAX AC, below 6.3.24 for airMAX M, below 1.2.3 for airFiber AF60-XG, or below 2.6.8 for airFiber AF60
  3. Confirm the wireless radio is enabled
    In the web UI, navigate to the Wireless tab or Wireless Settings and verify that the radio is not disabled. Alternatively, run 'show wireless' via CLI to check radio status
    Affected if The wireless interface is enabled (this is the default state on affected devices)
  4. Compare against affected version ranges
    Match your identified device model and firmware version against the affected ranges: airMAX AC < 8.7.21, airMAX M < 6.3.24, airFiber AF60-XG < 1.2.3, airFiber AF60 < 2.6.8
    Affected if Your device model matches one of the affected products AND the installed version falls below the corresponding patched version

If the device is an airMAX or airFiber model running firmware below the patched version and has its wireless radio enabled, the environment is affected by this CVE.

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 1.2.3 / 2.6.8 / 6.3.24 or later
Fixed in 1.2.32.6.86.3.24
Interim mitigation

Restrict physical/wireless access to affected devices, apply vendor firmware updates when available, and monitor for unauthorized wireless clients in proximity.

Recommended fix High confidence

airMAX AC: 8.7.21 | airMAX M: 6.3.24 | airFiber AF60-XG: 1.2.3 | airFiber AF60: 2.6.8

  1. 1. Identify the exact Ubiquiti device model (airMAX AC, airMAX M, airFiber AF60-XG, or airFiber AF60)
  2. 2. Access the device's web management interface or CLI
  3. 3. Check the current firmware version running on the device
  4. 4. Download the appropriate fixed firmware version from Ubiquiti's official support site: 8.7.21 for airMAX AC, 6.3.24 for airMAX M, 1.2.3 for airFiber AF60-XG, or 2.6.8 for airFiber AF60
  5. 5. Upload the firmware file through the device's web interface (System > Firmware) or CLI using the upgrade command
  6. 6. Wait for the firmware upload and installation to complete; do not power off the device during this process
  7. 7. After reboot, verify the new firmware version is installed and the device is operating normally
Caveat Firmware upgrades typically carry low risk but always backup configuration before updating; test in a non-production environment first

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

Fix this in Airmax Ac Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,770
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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-2026-21639 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