Skip to content
Noroxi
CVE-2021-34779· NVD / CVE Program· CNA cisco

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.

HighCVSS 8.8 · v3.1—No exploit No fix recorded
Published
Oct 6, 2021
Updated
Jun 16, 2026
EPSS
0.5% · 42th percentile
Follow this CVE

Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.

Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
8.8
CNA · cisco
4.3
4.5 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Affected systems

VendorProduct
ciscobusiness 220-8t-e-2g firmware
ciscobusiness 220-8t-e-2g
ciscobusiness 220-8p-e-2g firmware
ciscobusiness 220-8p-e-2g
ciscobusiness 220-8fp-e-2g firmware
ciscobusiness 220-8fp-e-2g
ciscobusiness 220-16t-2g firmware
ciscobusiness 220-16t-2g
ciscobusiness 220-16p-2g firmware
ciscobusiness 220-16p-2g
ciscobusiness 220-24t-4g firmware
ciscobusiness 220-24t-4g

and 20 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cisco business 220-16p-2g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-16t-2g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-24fp-4g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-24fp-4x firmwareup to 1.2.0.6 inclusive
  • cisco business 220-24p-4g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-24p-4x firmwareup to 1.2.0.6 inclusive
  • cisco business 220-24t-4g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-24t-4x firmwareup to 1.2.0.6 inclusive
  • cisco business 220-48fp-4x firmwareup to 1.2.0.6 inclusive
  • cisco business 220-48p-4g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-48p-4x firmwareup to 1.2.0.6 inclusive
  • cisco business 220-48t-4g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-48t-4x firmwareup to 1.2.0.6 inclusive
  • cisco business 220-8fp-e-2g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-8p-e-2g firmwareup to 1.2.0.6 inclusive
  • cisco business 220-8t-e-2g firmwareup to 1.2.0.6 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.

  • Cisco Cisco Small Business 200 Series Smart Switches

    • n/aaffected

Same product

cisco: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-34780Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities
    35Monitor
  • CVE-2021-34757Cisco Business 220 Series Smart Switches Static Key and Password Vulnerabilities
    22Monitor
  • CVE-2021-34744Cisco Business 220 Series Smart Switches Static Key and Password Vulnerabilities
    19Monitor
  • CVE-2021-34778Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities
    17Monitor
  • CVE-2021-34777Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities
    17Monitor
  • CVE-2021-34776Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

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

nvd-primary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
char buf[256];memcpy(buf, pkt->data, pkt->len);

Fixed

c
char buf[256];if (pkt->len > sizeof(buf)) {  return -EINVAL;}memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records