CVE intelligence

CVE-2026-20173

Vulnerability intelligence

Published Oct 7, 2026Sources checked Oct 7, 2026

5.8MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-20173 and is rated Medium severity with a CVSS score of 5.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Cisco Security Advisories guidance

Vendor revision: Oct 7, 2026

To remediate the vulnerabilities that were disclosed on October 7, 2026, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories.

Cisco Security Advisories guidance

Vendor revision: Oct 7, 2026

Cisco has released software updates that address this vulnerability.

CISA KEVNot listedBased on the latest collected catalog

EPSSUnavailableNo current score collected

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-20173?

A vulnerability in Cisco NX-OS Software could allow an unauthenticated, remote attacker to exhaust system resources, causing a denial of service (DoS) condition. This vulnerability exists because rate limiting was improperly applied to some protocols. An attacker could exploit this vulnerability by sending a high rate of UDP or TCP connections to a data plane interface on an affected device. A successful exploit could allow the attacker to cause instability to various routing and control plane protocols through some packet loss and temporary disruptions, causing a DoS condition. This DoS condition will clear without manual intervention soon after the high rate of traffic is stopped.

Source: NVD