CVE-2021-34776
Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities
- Published
- Updated
- Reserved
- Assigned by
- cisco
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.
Timeline
ID reserved
By cisco
- 4 months later
· 4 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ciscoCNA (assigner) | 3.1 | Medium4.3 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium4.3 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.41% · top 64% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.3.
Weakness
Affected products
Cisco · Cisco Small Business 200 Series Smart Switches
- affected n/a
What to do
Exploitation: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
References (1)
- 20211006 Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol Vulnerabilities (opens in a new tab)vendor-advisoryx_refsource_CISCOx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-34776)Record last updated .