dbcve.org
Fabric Operating SystemOperating system · Broadcom

CVE-2021-27795

HIGH · 8.1 CVSS v3.1 Published 2023-12-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable 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
Brocade Fabric OS (FOS) hardware platforms running any version of Brocade Fabric OS software, which supports the license string format; contain cryptographic issues that could allow for the installation of forged or fraudulent license keys. This would allow attackers or a malicious party to forge a counterfeit license key that the Brocade Fabric OS platform would authenticate and activate as if it were a legitimate license key.

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

Brocade Fabric OS contains cryptographic weaknesses in its license key validation mechanism that allows attackers to forge or craft fraudulent license keys that the system will authenticate and activate as legitimate, effectively bypassing the cryptographic signature verification.

MitigationApply vendor-provided patches for Brocade Fabric OS when available; verify integrity of all installed license keys; implement additional out-of-band validation for license authenticity; monitor for unauthorized license activations.

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
Fabric Operating SystemOperating system
Affected:all versions

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/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 if Brocade Fabric OS is installed
    Run 'version' or 'firmwareShow' command on the fabric switch to confirm the operating system and its version
    Affected if The system is running any version of Brocade Fabric OS (all versions are affected)
  2. List all installed license keys
    Execute 'licenseShow' or equivalent command to display all active license keys currently installed on the system
    Affected if Any license keys are installed - the vulnerability allows forging license keys that will be accepted as legitimate
  3. Audit license key properties
    Use 'licenseShow -detail' or similar command to inspect the license signature, key ID, and activation timestamp for each installed license
    Affected if Licenses display details without cryptographic validation errors - the vulnerability bypasses signature verification
  4. Check for unexpected or unauthorized licenses
    Review the license list for any licenses that were not intentionally purchased or installed, comparing against known procurement records
    Affected if Any license exists that was not explicitly authorized or purchased through official channels
  5. Verify license integrity with vendor
    Contact Broadcom/VMware support to validate the authenticity of installed license keys using their out-of-band verification tools
    Affected if Vendor confirms any license key is invalid or fraudulent - indicating the vulnerability was exploited

If the system runs Brocade Fabric OS with any installed license keys, the environment is potentially affected because all versions contain the cryptographic weakness in license validation that allows forged keys to be accepted as legitimate.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-provided patches for Brocade Fabric OS when available; verify integrity of all installed license keys; implement additional out-of-band validation for license authenticity; monitor for unauthorized license activations.

Fix this in Fabric Operating System Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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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-2021-27795 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