CVE-2021-40120 : A vulnerability in the web-based management interface of certain Cisco Small Bus

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.

Published 2021-11-04 16:15:09

Updated 2022-08-05 11:45:51

Source Cisco Systems, Inc.

View at NVD, CVE.org

Vulnerability category: Input validation

Products affected by CVE-2021-40120

Cisco » Ios Xr » Version: 4.2.3.06
cpe:2.3:o:cisco:ios_xr:4.2.3.06:*:*:*:*:*:*:*
Matching versions
When used together with: Cisco » Rv016 » Version: N/A
When used together with: Cisco » Rv042 » Version: N/A
When used together with: Cisco » Rv042g » Version: N/A
When used together with: Cisco » Rv082 » Version: N/A
When used together with: Cisco » Rv320 » Version: N/A
When used together with: Cisco » Rv325 » Version: N/A
Cisco » Application Extension Platform » Version: 1.5.1.13
cpe:2.3:a:cisco:application_extension_platform:1.5.1.13:*:*:*:*:*:*:*
Matching versions

Exploit prediction scoring system (EPSS) score for CVE-2021-40120

EPSS FAQ

0.18%

Probability of exploitation activity in the next 30 days EPSS Score History

~ 55 %

Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-40120

Base Score	Base Severity	CVSS Vector	Exploitability Score	Impact Score	Score Source
9.0	HIGH	AV:N/AC:L/Au:S/C:C/I:C/A:C	8.0	10.0	NIST
Access Vector: Network Access Complexity: Low Authentication: Single Confidentiality Impact: Complete Integrity Impact: Complete Availability Impact: Complete
6.5	MEDIUM	CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N	1.2	5.2	Cisco Systems, Inc.
Attack Vector: Network Attack Complexity: Low Privileges Required: High User Interaction: None Scope: Unchanged Confidentiality: High Integrity: High Availability: None
7.2	HIGH	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H	1.2	5.9	NIST
Attack Vector: Network Attack Complexity: Low Privileges Required: High User Interaction: None Scope: Unchanged Confidentiality: High Integrity: High Availability: High

CWE ids for CVE-2021-40120

CWE-20 Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Assigned by: ykramarz@cisco.com (Secondary)
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Assigned by: nvd@nist.gov (Primary)

References for CVE-2021-40120

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sbrv-cmdinjection-Z5cWFdK

Cisco Small Business RV Series Routers Command Injection Vulnerability
Vendor Advisory

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Vulnerability Details : CVE-2021-40120

Products affected by CVE-2021-40120

Exploit prediction scoring system (EPSS) score for CVE-2021-40120

CVSS scores for CVE-2021-40120

CWE ids for CVE-2021-40120

References for CVE-2021-40120