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FortiwlcApplication · Fortinet

CVE-2021-26093

MEDIUM · 6.5 CVSS v3.1 Published 2024-12-19
Fix available
A fix is available. Upgrade to 8.6.3 or later.
See remediation →
67/100
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
An access of uninitialized pointer (CWE-824) vulnerability in FortiWLC versions 8.6.0, 8.5.3 and earlier may allow a local and authenticated attacker to crash the access point being managed by the controller by executing a crafted CLI command.

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 · high confidence

An access of uninitialized pointer (CWE-824) vulnerability in FortiWLC versions 8.6.0, 8.5.3 and earlier allows a local authenticated attacker to crash managed access points by executing a crafted CLI command. This is a denial-of-service vulnerability requiring local access and valid credentials.

MitigationUpgrade FortiWLC to a patched version. Additionally, restrict CLI access to trusted personnel and monitor for unusual or malformed CLI commands that may indicate exploitation attempts.

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:>= 8.0.6, < 8.6.3

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
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/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 installed FortiWLC version
    Run 'show system info' or 'get system status' via CLI to retrieve the firmware version
    Affected if Version is 8.0.6 through 8.6.2 inclusive (versions >= 8.0.6 and < 8.6.3)
  2. Confirm CLI access is enabled
    Check if the CLI service is accessible and running - verify via 'show cli global' or check management interface configuration for CLI-enabled interfaces
    Affected if CLI access is enabled and reachable (required for exploitation)
  3. Identify accounts with CLI privileges
    Review user accounts with CLI access using 'show admin' or enumerate administrative users configured on the system
    Affected if Any local authenticated user accounts exist with CLI execution privileges
  4. Check for AP crash events
    Review AP status via 'show ap status' or check system logs for unexpected AP disconnections or crashes occurring around the same time
    Affected if Managed access points are experiencing unexplained crashes or disconnections
  5. Review recent CLI command logs
    Examine CLI audit logs or command history for unusual or malformed CLI commands that could indicate exploitation attempts
    Affected if Suspicious or malformed CLI commands are present in logs

The environment is affected if FortiWLC version is 8.0.6 through 8.6.2, CLI access is enabled, and local authenticated credentials exist - all three conditions required for exploitation.

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 8.6.3 or later
Fixed in 8.6.3
Interim mitigation

Upgrade FortiWLC to a patched version. Additionally, restrict CLI access to trusted personnel and monitor for unusual or malformed CLI commands that may indicate exploitation attempts.

Recommended fix High confidence

FortiWLC 8.6.3 or later (8.6.x branch)

  1. Plan an upgrade to FortiWLC version 8.6.3 or later
  2. Back up the current controller configuration
  3. Review Fortinet's upgrade documentation for FortiWLC
  4. Execute the upgrade following vendor procedures
  5. Verify the upgrade was successful and the vulnerability is resolved
Caveat Review release notes for any breaking changes between your current version and 8.6.3

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

Fix this in Fortiwlc Scoped from the published advisory
  • Consultation3.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,950
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,120.

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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-2021-26093 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