Cisco Small Business RV Series Routers Command Injection Vulnerability

published 2021-11-04 5y ago modified 2026-06-17 4mo ago also EUVD-2021-27307

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.0%; EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits: 0; none known

A vulnerability in the web-based management interface of certain Cisco Small Business RV Series Routers could allow an authenticated, remote attacker with administrative privileges to inject arbitrary commands into the underlying operating system and execute them using root-level privileges. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending malicious input to a specific field in the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying Linux operating system as a user with root-level privileges.

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CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 2y ago (2024-11-07)

Exploit prediction

2.00% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
NVD	3.1	7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	9.0	AV:N/AC:L/Au:S/C:C/I:C/A:C

Affected products

Cisco Cisco Small Business RV Series Router Firmware

Classification

Weakness

CWE-20 Improper Input Validation
CWE-78 Improper Neutralization of Special Elements used in an OS Command

Technology feeds

Cisco IOS rss critical rss

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-sbrv-cmdinjection-Z5cWFdK
vendor-advisory

Sources

CVE List CVE-2021-40120
NVD CVE-2021-40120

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