CVE-2021-1586: Cisco NX-OS

High severity, CVSS 8.6. EPSS: 2.5% chance of exploitation in the next 30 days.

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.

Affected products

• Cisco NX-OS: version 15.0(2e) only; version 15.1(1h) only

Published 2021-08-25. Last modified 2026-06-17.