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FortiwlcApplication · Fortinet

CVE-2021-22126

MEDIUM · 6.7 CVSS v3.1 Published 2025-03-17
Fix available
A fix is available. Upgrade to 8.5.3 or later.
See remediation →
69/100
Remediation priority · Elevated
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 use of hard-coded password vulnerability in FortiWLC version 8.5.2 and below, version 8.4.8 and below, version 8.3.3 to 8.3.2, version 8.2.7 to 8.2.6 may allow a local, authenticated attacker to connect to the managed Access Point (Meru AP and FortiAP-U) as root using the default hard-coded username and password.

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

FortiWLC versions 8.5.2 and below contain hard-coded credentials that allow a local, authenticated attacker to gain root access to managed Meru AP and FortiAP-U access points using a default username and password pair.

MitigationChange the hard-coded default credentials on affected FortiWLC installations and managed access points immediately. Implement least-privilege access controls and consider upgrading to a patched version if available.

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
FortiwlcApplication
Affected:>= 8.4.0, < 8.5.3= 8.2.6= 8.2.7= 8.3.2= 8.3.3

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

CVSS:3.1/AV:L/AC:L/PR:H/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 FortiWLC installation
    Check if FortiWLC (Wireless LAN Controller) is running on the system. Look for processes named 'fwnsd' or 'fwlc', or check system services for FortiWLC-related services.
    Affected if FortiWLC software is installed and running
  2. Check FortiWLC version
    Run 'show system version' or 'get system status' from the FortiWLC CLI, or check the web UI system information page for the firmware version.
    Affected if Version matches >= 8.4.0 and < 8.5.3, or equals 8.2.6, 8.2.7, 8.3.2, or 8.3.3
  3. Verify hard-coded credential presence
    Attempt to authenticate to managed APs (Meru AP or FortiAP-U) using the default hard-coded credentials. In FortiWLC CLI, use 'wlancfg -s' or check AP configuration files in /var/fos/ for stored credentials.
    Affected if Default username/password pair (such as 'root' with a known hard-coded password) is present and allows AP access
  4. Check managed AP access
    From FortiWLC, list managed access points with 'show ap all' or via the web UI, then attempt SSH or console access to a managed AP using the suspected hard-coded credentials.
    Affected if Authentication succeeds with default credentials granting root access to managed APs

If FortiWLC version is 8.2.6, 8.2.7, 8.3.2, 8.3.3, or between 8.4.0 and 8.5.2, and default hard-coded credentials allow root access to managed APs, the environment is affected.

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 8.5.3 or later
Fixed in 8.5.3
Interim mitigation

Change the hard-coded default credentials on affected FortiWLC installations and managed access points immediately. Implement least-privilege access controls and consider upgrading to a patched version if available.

Recommended fix Moderate confidence

FortiWLC 8.5.3 or later (e.g., 8.5.4, 8.6.x)

  1. 1. Identify the current FortiWLC version using 'show version' or the web UI dashboard.
  2. 2. Schedule a maintenance window for the upgrade (FortiWLC upgrades typically require brief downtime).
  3. 3. Backup the current configuration via 'backup config' command or web UI.
  4. 4. Obtain the firmware image for FortiWLC version 8.5.3 or later from Fortinet support portal (support.fortinet.com).
  5. 5. Upload the new firmware through the web UI (System > Maintenance > Firmware) or CLI using 'upgrade image <image_file>'.
  6. 6. Reboot the system to apply the new firmware.
  7. 7. After reboot, verify the new version is running: 'show version'.
  8. 8. Verify the hard-coded credentials are no longer present by checking for default credentials in the AP management configuration.
Caveat Standard upgrade - review Fortinet release notes for any configuration or feature changes between your version and 8.5.3

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

Fix this in Fortiwlc Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2021-22126 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