CVE-2026-20033: Cisco NX-OS System Software In ACI Mode

High severity, CVSS 7.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A vulnerability in Cisco Nexus 9000 Series Fabric Switches in ACI mode could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient validation when processing specific Ethernet frames. An attacker could exploit this vulnerability by sending a crafted Ethernet frame to the management interface of an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. Note: Only the out-of-band (OOB) management interface is affected.

Affected products

• Cisco Cisco NX-OS System Software In ACI Mode: version 15.2(1g) only; version 15.2(2e) only; version 15.2(2f) only; version 15.2(2g) only; version 15.2(2h) only; version 15.2(3f) only; …

Published 2026-02-25. Last modified 2026-06-17.