dbcve.org
Fabric Operating SystemOperating system · Broadcom

CVE-2021-27798

MEDIUM · 5.5 CVSS v3.1 Published 2022-08-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
57/100
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 vulnerability in Brocade Fabric OS versions 7.4.1b and 7.3.1d could allow local users to conduct privileged directory transversal. Brocade Fabric OS versions 7.4.1.x and 7.3.x have reached end of life. Brocade Fabric OS Users should upgrade to supported versions as described in the Product End-of-Life published report.

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

This is a local privilege escalation vulnerability in Brocade Fabric OS allowing privileged directory transversal. Local users can potentially escape directory restrictions and access files outside their intended scope, possibly with elevated privileges. The vulnerability exists in specific point releases (7.4.1b and 7.3.1d) of the Fabric OS firmware.

MitigationSince versions 7.4.1.x and 7.3.x are end-of-life, organizations must upgrade to a currently supported Brocade Fabric OS version as specified in the Product End-of-Life report. This is the only remediation path as no workarounds are mentioned.

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:= 7.3.1d= 7.4.1b

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
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 Fabric OS firmware version
    Use the CLI command to display the firmware version (such as 'version' or 'firmwareShow' or check the switch startup banner). Record the full version string including any point release suffixes.
    Affected if The version displayed is exactly 7.3.1d or exactly 7.4.1b (these are the specific vulnerable point releases).
  2. Confirm the exact point release
    Verify that the version string matches exactly '7.3.1d' or '7.4.1b' rather than nearby versions like 7.3.1c or 7.4.1a. Check both the major.minor.point and the letter suffix.
    Affected if The firmware version string is precisely '7.3.1d' or '7.4.1b'. Other versions in the 7.3.x or 7.4.x family are not affected unless they match these exact point releases.
  3. Check if local user authentication is enabled
    Determine whether local user accounts (as opposed to central directory services like LDAP/AD) are configured and enabled on the Fabric OS switch for administrative or operator access.
    Affected if Local user accounts exist and can log in to the switch. The vulnerability allows a local user to escape directory restrictions.
  4. Identify the switch model and management accessibility
    Document the Brocade switch model(s) in the environment and verify which ones run Fabric OS firmware. Confirm if you have CLI or web management access to query the version.
    Affected if The affected switch runs Fabric OS and you can query its firmware version. This is a local privilege escalation requiring authenticated local access.

You are affected if your Fabric OS firmware version is exactly 7.3.1d or exactly 7.4.1b, and local user authentication is enabled allowing an authenticated local user to attempt directory transversal.

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

Since versions 7.4.1.x and 7.3.x are end-of-life, organizations must upgrade to a currently supported Brocade Fabric OS version as specified in the Product End-of-Life report. This is the only remediation path as no workarounds are mentioned.

Fix this in Fabric Operating System Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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Scan for this in your stack

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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-2021-27798 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