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CVE-2021-34777: Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities
- Severity: medium (CVSS 4.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-10-06 · updated 2026-06-17
- Weakness: CWE-120
Description
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.
Affected products
- Cisco Business 220-16P-2G Firmware: through 1.2.0.6
- Cisco Business 220-16T-2G Firmware: through 1.2.0.6
- Cisco Business 220-24Fp-4G Firmware: through 1.2.0.6
- Cisco Business 220-24Fp-4X Firmware: through 1.2.0.6
- Cisco Business 220-24P-4G Firmware: through 1.2.0.6
- Cisco Business 220-24P-4X Firmware: through 1.2.0.6
- Cisco Business 220-24T-4G Firmware: through 1.2.0.6
- Cisco Business 220-24T-4X Firmware: through 1.2.0.6
- Cisco Business 220-48Fp-4X Firmware: through 1.2.0.6
- Cisco Business 220-48P-4G Firmware: through 1.2.0.6
- Cisco Business 220-48P-4X Firmware: through 1.2.0.6
- Cisco Business 220-48T-4G Firmware: through 1.2.0.6
- Cisco Business 220-48T-4X Firmware: through 1.2.0.6
- Cisco Business 220-8Fp-E-2G Firmware: through 1.2.0.6
- Cisco Business 220-8P-E-2G Firmware: through 1.2.0.6
- Cisco Business 220-8T-E-2G Firmware: through 1.2.0.6
References
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb220-lldp-multivuls-mVRUtQ8T
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb220-lldp-multivuls-mVRUtQ8T
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