dbcve.org
Fabric Operating SystemOperating system · Broadcom

CVE-2021-27792

HIGH · 7.8 CVSS v3.1 Published 2021-08-12
Fix available
A fix is available. Upgrade to 7.4.2h / 8.2.3a or later.
See remediation →
80/100
Remediation priority · High
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
The request handling functions in web management interface of Brocade Fabric OS versions before v9.0.1a, v8.2.3a, and v7.4.2h do not properly handle malformed user input, resulting in a service crash. An authenticated attacker could use this weakness to cause the FOS HTTP application handler to crash, requiring a reboot.

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

Brocade Fabric OS web management interface contains a flaw in request handling functions where malformed user input causes the FOS HTTP application handler to crash, requiring a system reboot to recover. This is a denial-of-service vulnerability that requires an authenticated attacker.

MitigationUpgrade to Fabric OS v9.0.1a, v8.2.3a, v7.4.2h or later. Additionally, restrict access to the management interface to trusted users only to reduce attack surface.

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:< 7.4.2h>= 8.0.0, < 8.2.3a>= 9.0.0, < 9.0.1a

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
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 Fabric OS installation
    Log into the device CLI and run the command 'version' or 'firmwareversion' to confirm Brocade Fabric OS is installed.
    Affected if The device is not running Fabric OS.
  2. Determine the Fabric OS version
    Execute the 'version' command and note the full version string (for example, 8.2.3a, 9.0.0, 7.4.1b). Compare it against the affected ranges: < 7.4.2h, >= 8.0.0 and < 8.2.3a, >= 9.0.0 and < 9.0.1a.
    Affected if The installed version falls within < 7.4.2h, >= 8.0.0 to < 8.2.3a, or >= 9.0.0 to < 9.0.1a.
  3. Verify the web management interface is enabled
    Run the command 'webapi status' or 'httpcfg' in the Fabric OS CLI to check if the HTTP/HTTPS management interface is currently active.
    Affected if The web management interface (HTTP or HTTPS) is enabled and the version is in the affected range.
  4. Confirm authentication access to the management interface
    Review user accounts with web interface access using 'userconfig --show' or check if remote authentication (RADIUS, TACACS+) is configured. The vulnerability requires an authenticated attacker.
    Affected if Untrusted or weak credentials exist with access to the web management interface on an affected version.

The environment is affected if the Fabric OS version is in the range < 7.4.2h, >= 8.0.0 to < 8.2.3a, or >= 9.0.0 to < 9.0.1a AND the web management interface is enabled with accessible authenticated users.

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 7.4.2h / 8.2.3a / 9.0.1a or later
Fixed in 7.4.2h8.2.3a9.0.1a
Interim mitigation

Upgrade to Fabric OS v9.0.1a, v8.2.3a, v7.4.2h or later. Additionally, restrict access to the management interface to trusted users only to reduce attack surface.

Recommended fix High confidence

Upgrade to Fabric OS 7.4.2h, 8.2.3a, or 9.0.1a (whichever is the appropriate release for your hardware platform branch)

  1. 1. Back up the current Fabric OS configuration using the 'configupload' command
  2. 2. Obtain the appropriate Fabric OS firmware upgrade file from Broadcom support portal (version 7.4.2h, 8.2.3a, or 9.0.1a depending on your current branch)
  3. 3. Transfer the upgrade file to the switch using FTP, SCP, or USB media
  4. 4. Verify the firmware file integrity using 'firmwarehash' or similar validation command
  5. 5. Initiate the firmware upgrade using 'firmwaredownload' command or through the web management interface
  6. 6. Monitor the upgrade process until completion - do not interrupt power or reboot during this process
  7. 7. After upgrade completes, verify the new firmware version using 'version' command
  8. 8. Validate that the web management interface is functioning properly
Caveat Fabric OS upgrades require planned downtime and should be tested in a non-production environment first; always review Broadcom compatibility and upgrade guidelines for your specific hardware model

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

Fix this in Fabric Operating System Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2021-27792 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