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CVE-2021-34778

Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities

4.3 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Adjacent network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

0.41%Down 0.3 points since Oct 7, 2021
90%50%10%1%

What each source reports

CVE List Score used 4.3

Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities

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.

Record
CVE-2021-34778
CVSS 3.1
4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-120
Updated
2026-11-02
EUVDEUVD-2021-21428 4.3

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.

Record
EUVD-2021-21428
CVSS 3.1
4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-jr9h-58gc-725g No score

Multiple vulnerabilities exist in the Link Layer Discovery Protocol (LLDP) implementation for...

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.

Record
GHSA-jr9h-58gc-725g
Weakness
CWE-120
Updated
2026-11-02
NVD 4.3

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.

Record
CVE-2021-34778
CVSS 3.1
4.3 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS 2.0
2.9 LowAV:A/AC:M/Au:N/C:N/I:P/A:N
Weakness
CWE-120
Updated
2026-11-02

Affected products

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History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-34778 is a medium vulnerability (CVSS 4.3) in Cisco Business 220-16p-2g Firmware, published October 6, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. No source names a fixed version.

References

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