CVE-2021-1591

Cisco Nexus 9500 Series Switches Access Control List Bypass Vulnerability

Severity Score

5.3

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthenticated, remote attacker to bypass access control list (ACL) rules that are configured on an affected device. This vulnerability is due to oversubscription of resources that occurs when applying ACLs to port channel interfaces. An attacker could exploit this vulnerability by attempting to access network resources that are protected by the ACL. A successful exploit could allow the attacker to access network resources that would be protected by the ACL that was applied on the port channel interface.

Una vulnerabilidad en la lógica de suscripción de puertos EtherChannel de Cisco Nexus 9500 Series Switches podría permitir a un atacante remoto no autenticado omitir las reglas de la lista de control de acceso (ACL) configuradas en un dispositivo afectado. Esta vulnerabilidad es debido a la sobresuscripción de recursos que ocurre cuando se aplican las ACL a las interfaces del canal de puertos. Un atacante podría explotar esta vulnerabilidad al intentar acceder a los recursos de red que están protegidos por la ACL. Una explotación con éxito podría permitir al atacante acceder a los recursos de red que estarían protegidos por la ACL que se aplicó en la interfaz del canal de puertos.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

None

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2020-11-13 CVE Reserved
2021-08-25 CVE Published
2024-05-10 EPSS Updated
2024-11-07 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-284: Improper Access Control

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nexus-acl-vrvQYPVe	2023-11-07

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	9.3\(4\) Search vendor "Cisco" for product "Nx-os" and version "9.3\(4\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9500 16-slot Search vendor "Cisco" for product "Nexus 9500 16-slot"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	9.3\(4\) Search vendor "Cisco" for product "Nx-os" and version "9.3\(4\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9500 4-slot Search vendor "Cisco" for product "Nexus 9500 4-slot"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	9.3\(4\) Search vendor "Cisco" for product "Nx-os" and version "9.3\(4\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9500 8-slot Search vendor "Cisco" for product "Nexus 9500 8-slot"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	9.3\(4\) Search vendor "Cisco" for product "Nx-os" and version "9.3\(4\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9504 Search vendor "Cisco" for product "Nexus 9504"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	9.3\(4\) Search vendor "Cisco" for product "Nx-os" and version "9.3\(4\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9508 Search vendor "Cisco" for product "Nexus 9508"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	9.3\(4\) Search vendor "Cisco" for product "Nx-os" and version "9.3\(4\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9516 Search vendor "Cisco" for product "Nexus 9516"	-	-	Safe