Cisco Small Business RV Series Routers Link Layer Discovery Protocol Vulnerabilities

published 2021-04-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-6718

cvss: 7.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

Multiple vulnerabilities exist in the Link Layer Discovery Protocol (LLDP) implementation for Cisco Small Business RV Series Routers. An unauthenticated, adjacent attacker could execute arbitrary code or cause an affected router to leak system memory or reload. A memory leak or device reload would cause a denial of service (DoS) condition on an 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).

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-11-08)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.4	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	3.1	7.4	CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	2.0	6.1	AV:A/AC:L/Au:N/C:N/I:N/A:C

Affected products

Cisco Cisco Small Business RV Series Router Firmware

Classification

Weakness

CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-401 Missing Release of Memory after Effective Lifetime

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-multi-lldp-u7e4chCe
vendor-advisory

Sources

CVE List CVE-2021-1251
NVD CVE-2021-1251

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Summary