CVE-2021-27792Network attack vector

Authenticated service crash via malformed web requests

Published Aug 12, 2021 · Updated Aug 3, 2024

Denial of service in Brocade Fabric OS releases before 7.4.2h, 8.2.3a, or 9.0.1a allows remote authenticated users to crash its web service. Web-management request handlers do not safely reject malformed user input, causing the FOS HTTP application handler to terminate. Access to the authenticated web-management interface is required, and recovery from the handler crash requires a switch reboot.

CVSS severity5.3
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Brocade Fabric OS releases before 7.4.2h, 8.2.3a, or 9.0.1a allows remote authenticated users to crash its web service. Web-management request handlers do not safely reject malformed user input, causing the FOS HTTP application handler to terminate. Access to the authenticated web-management interface is required, and recovery from the handler crash requires a switch reboot.

The record

CVE
CVE-2021-27792
Published
Aug 12, 2021
Updated
Aug 3, 2024
Vendor
Brocade Communications Systems
Product
Brocade Fabric OS
Classifications
T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Brocade Fabric OS versions before v9.0.1a, and v8.2.3a, and v7.4.2h

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Brocade Communications Systems · Brocade Fabric OSversion=Brocade Fabric OS versions before v9.0.1a, and v8.2.3a, and v7.4.2h

Published CVSS scores

5.3BroadcomCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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