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Business 220 8t E 2g FirmwareOperating system · Cisco

CVE-2021-34780

HIGH · 8.8 CVSS v3.1 Published 2021-10-06
Fix available
A fix is available. Upgrade to after 1.2.0.6 or later.
See remediation →
93/100
Remediation priority · Urgent
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
Multiple vulnerabilities exist in the Link Layer Discovery Protocol (LLDP) implementation for Cisco Small Business 220 Series Smart Switches. An unauthenticated, adjacent attacker could perform the following: Execute code on the affected device or cause it to reload unexpectedly Cause LLDP database corruption on the affected device For more information about these vulnerabilities, see the Details section of this advisory. Note: LLDP is a Layer 2 protocol. To exploit these vulnerabilities, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent). Cisco has released firmware updates that address these vulnerabilities.

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

Multiple vulnerabilities in the LLDP implementation of Cisco Small Business 220 Series Smart Switches allow an unauthenticated, Layer 2 adjacent attacker to execute arbitrary code, cause unexpected device reloads (DoS), or corrupt the LLDP database. The CVSS 8.8 score reflects the high impact of code execution combined with the adjacent network requirement.

MitigationApply the Cisco firmware update for the 220 Series Smart Switches. As a compensating control, limit Layer 2 adjacency by segmenting vulnerable devices or disabling LLDP on untrusted ports until the update can be applied.

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
Business 220 8t E 2g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 8p E 2g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 8fp E 2g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 16t 2g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 16p 2g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 24t 4g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 24p 4g FirmwareOperating system
Affected:<= 1.2.0.6
Business 220 24fp 4g FirmwareOperating system
Affected:<= 1.2.0.6

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/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 the switch model
    Physically inspect the device or access the web GUI/CLI to confirm the model is a Cisco Business 220 series switch (such as 220 8t, 220 8p, 220 8fp, 220 16t, 220 16p, 220 24t, 220 24p, or 220 24fp).
    Affected if The device is any Cisco Business 220 series model listed in the affected products.
  2. Check the firmware version
    Access the switch web interface under Administration > Firmware Upgrade, or use the CLI command 'show version' to retrieve the installed firmware version.
    Affected if The firmware version is 1.2.0.6 or lower.
  3. Verify LLDP is enabled
    Access the switch web GUI under Port Management > LLDP, or use the CLI command 'show lldp' to check whether LLDP is enabled globally or on any ports.
    Affected if LLDP is enabled on the switch or on any port.

You are affected if you have a Cisco Business 220 series switch running firmware version 1.2.0.6 or lower with LLDP enabled on the device or any of its ports.

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 a release after 1.2.0.6
Interim mitigation

Apply the Cisco firmware update for the 220 Series Smart Switches. As a compensating control, limit Layer 2 adjacency by segmenting vulnerable devices or disabling LLDP on untrusted ports until the update can be applied.

Recommended fix Moderate confidence

Any firmware version higher than 1.2.0.6 (contact Cisco for the exact fixed release)

  1. Verify the current firmware version on the affected Cisco Small Business 220 Series Smart Switch by accessing the web-based management interface or using CLI commands
  2. Download the latest firmware version from Cisco's official support website (tools.cisco.com) or the Cisco firmware download center
  3. Backup the current device configuration before performing the firmware upgrade
  4. Upload the new firmware file through the switch's web interface or TFTP upgrade process
  5. Verify the firmware upgrade was successful and the device is operating normally
  6. Confirm the LLDP service is functioning properly after the upgrade
Caveat Standard firmware upgrade risks apply - ensure configuration backup and plan for brief downtime during the upgrade process

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

Fix this in Business 220 8t E 2g Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,072.

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-2021-34780 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