CVE-2021-1586

mediumpriority · track · 35OT risk · elevatedEPSS 0.025 · 84 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.45% (84th) EPSS

CVSS 5 · medium

Is it mine?

85 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · cisco_csaf

EPSS · scored 2026-10-22

A vulnerability in the Multi-Pod or Multi-Site network configurations for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to unexpectedly restart the device, resulting in a denial of service (DoS) condition. This vulnerability exists because TCP traffic sent to a specific port on an affected device is not properly sanitized. An attacker could exploit this vulnerability by sending crafted TCP data to a specific port that is listening on a public-facing IP address for the Multi-Pod or Multi-Site configuration. A successful exploit could allow the attacker to cause the device to restart unexpectedly, resulting in a DoS condition.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedCisco NX-OS System Software in ACI Mode 13.2(10e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(10f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(10g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(1l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(1m) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(2l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(2o) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(3i) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(3j) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(3n) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(3o) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(3r) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(3s) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(41d) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(4d) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(4e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(5d) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(5e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(5f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(6i) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(7f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(7k) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(8d) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(9b) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(9f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 13.2(9h) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.0(1h) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.0(2c) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.0(3c) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.0(3d) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(1i) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(1j) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(1k) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(1l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2m) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2o) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2s) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2u) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2w) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.1(2x) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(1i) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(1j) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(1l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(2e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(2f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(2g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(3j) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(3l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(3n) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(3q) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(4i) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(4k) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(4o) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(4p) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(5k) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(5l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(5n) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(6d) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(6g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(6h) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(6l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(6o) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(7f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(7l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(7q) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 14.2(7r) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.0(1k) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.0(1l) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.0(2e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.0(2h) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.1(2e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.1(3e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.1(4c) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(1g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(2e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(2f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(2g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(2h) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(3e) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(3f) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedCisco NX-OS System Software in ACI Mode 15.2(3g) when installed on Cisco Nexus 9000 Series Switchescisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

cvss

Technical severity, 0–10. One row per scoring source.

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–8.6

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 4

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4

v3.17.9highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-345USprimary

affected products (85)

Products and version ranges known to be affected.

showing 20 of 85

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-n9kaci-tcp-dos-YXukt6gMCisco Nexus 9000 Series Fabric Switches ACI Mode Multi-Pod and Multi-Site TCP Denial of Service Vulnerability2021-08-25csaf · cisco_csafUS
February 23, 2022 Update: After further investigation, Cisco determined that an additional fix was necessary to completely address this vulnerability. The initial fix allowed an attacker to cause high CPU utilization on an affected device, which could impact user traffic. See the Fixed Software ["#fs"] section of this advisory for updated information about the fixed releases. A vulnerability in the Multi-Pod or Multi-Site network configurations for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to unexpectedly restart the device, resulting in a denial of service (DoS) condition. This vulnerability exists because TCP traffic sent to a specific port on an affected device is not properly sanitized. An attacker could exploit this vulnerability by sending crafted TCP data to a specific port that is listening on a public-facing IP address for the Multi-Pod or Multi-Site configuration. A successful exploit could allow the attacker to cause the device to restart unexpectedly, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74640"].

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cisco_csaf NVD CVE.org MITRE

published 2021-08-25modified 2026-06-17

related (1,420)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2023-38831US	high7.8OT critical	99.8% (100th)	KEV	2023-08-23
RARLAB WinRAR before 6.23 allows attackers to execute arbitrary code when a user attempts to view a benign file within a ZIP archive. The issue occurs because a ZIP archive may inc…
CVE-2022-40139US	high7.2OT critical	3.29% (88th)	KEV	2022-09-19
Improper validation of some components used by the rollback mechanism in Trend Micro Apex One and Trend Micro Apex One as a Service clients could allow a Apex One server administra…
CVE-2022-26871US	critical9.8OT critical	19.5% (97th)	KEV	2022-03-29
An arbitrary file upload vulnerability in Trend Micro Apex Central could allow an unauthenticated remote attacker to upload an arbitrary file which could lead to remote code execut…
CVE-2019-5591US	medium6.5OT critical	18.6% (97th)	KEV	2020-08-14
A Default Configuration vulnerability in FortiOS may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the LDAP server.
CVE-2023-48795US	medium5.9OT high	93.5% (100th)	Exploit	2023-12-18
The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packet…

+1415 more

references (5)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan