CVE-2021-1523

Cisco Nexus 9000 Series Fabric Switches ACI Mode Queue Wedge Denial of Service Vulnerability

Severity Score

8.6

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

A vulnerability in Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, remote attacker to cause a queue wedge on a leaf switch, which could result in critical control plane traffic to the device being dropped. This could result in one or more leaf switches being removed from the fabric. This vulnerability is due to mishandling of ingress TCP traffic to a specific port. An attacker could exploit this vulnerability by sending a stream of TCP packets to a specific port on a Switched Virtual Interface (SVI) configured on the device. A successful exploit could allow the attacker to cause a specific packet queue to queue network buffers but never process them, leading to an eventual queue wedge. This could cause control plane traffic to be dropped, resulting in a denial of service (DoS) condition where the leaf switches are unavailable. Note: This vulnerability requires a manual intervention to power-cycle the device to recover.

Una vulnerabilidad en Cisco Nexus 9000 Series Fabric Switches en el Modo Application Centric Infrastructure (ACI), podría permitir a un atacante remoto no autenticado causar un acuñamiento de queues en un switch de hoja, que podría resultar en una caída del tráfico crítico del plano de control en el dispositivo. Esto podría dar lugar a que uno o más switches de hoja sean eliminados de la estructura. Esta vulnerabilidad es debido a un manejo inapropiado del tráfico TCP de entrada a un puerto específico. Un atacante podría explotar esta vulnerabilidad mediante el envío de un flujo de paquetes TCP a un puerto específico en una Switched Virtual Interface configurada en el dispositivo. Una explotación con éxito podría permitir al atacante causar que una queue de paquetes específica ponga en queue los búferes de red pero nunca los procese, conllevando a un eventual acuñamiento de queues. Esto podría causar que el tráfico del plano de control se caiga, resultando en una condición de denegación de servicio (DoS) donde los switches de la hoja no están disponibles. Nota: Esta vulnerabilidad requiere una intervención manual para apagar el dispositivo y recuperarlo.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-11-13 CVE Reserved
2021-08-25 CVE Published
2024-05-10 EPSS Updated
2024-09-16 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-772: Missing Release of Resource after Effective Lifetime

CAPEC

References (1)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n9kaci-queue-wedge-cLDDEfKF	2023-11-07

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"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 93120tx Search vendor "Cisco" for product "Nexus 93120tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 93128tx Search vendor "Cisco" for product "Nexus 93128tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9332pq Search vendor "Cisco" for product "Nexus 9332pq"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372px Search vendor "Cisco" for product "Nexus 9372px"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372px-e Search vendor "Cisco" for product "Nexus 9372px-e"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372tx Search vendor "Cisco" for product "Nexus 9372tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372tx-e Search vendor "Cisco" for product "Nexus 9372tx-e"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9396px Search vendor "Cisco" for product "Nexus 9396px"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	13.2\(3n\) Search vendor "Cisco" for product "Nx-os" and version "13.2\(3n\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9396tx Search vendor "Cisco" for product "Nexus 9396tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 93120tx Search vendor "Cisco" for product "Nexus 93120tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 93128tx Search vendor "Cisco" for product "Nexus 93128tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9332pq Search vendor "Cisco" for product "Nexus 9332pq"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372px Search vendor "Cisco" for product "Nexus 9372px"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372px-e Search vendor "Cisco" for product "Nexus 9372px-e"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372tx Search vendor "Cisco" for product "Nexus 9372tx"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9372tx-e Search vendor "Cisco" for product "Nexus 9372tx-e"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9396px Search vendor "Cisco" for product "Nexus 9396px"	-	-	Safe
Cisco Search vendor "Cisco"	Nx-os Search vendor "Cisco" for product "Nx-os"	14.2\(4i\) Search vendor "Cisco" for product "Nx-os" and version "14.2\(4i\)"	-	Affected	in	Cisco Search vendor "Cisco"	Nexus 9396tx Search vendor "Cisco" for product "Nexus 9396tx"	-	-	Safe