CVE-2026-20038: Cisco Nexus 9000 Series Fabric Switches in ACI Mode Policy-Based Redirect Endpoint Group Contract Bypass Vulnerability
A vulnerability in the endpoint group (EPG) contract functionality of Cisco Nexus 9000 Series Fabric Switches in ACI Mode could allow an unauthenticated, remote attacker to bypass configured EPG contracts. This vulnerability is due to an improper control with EPG contracts. An attacker could exploit this vulnerability by sending IPv4 or IPv6 packets using UDP source and destination ports that are assigned to DHCP traffic through an affected device. A successful exploit could allow the attacker to bypass EPG contracts on the affected device.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this vulnerability?
Cisco Nexus 9000 Series Fabric Switches operating in ACI Mode are affected. Exposure applies where EPG contracts are configured and traffic can reach the affected device.
What traffic is required to exploit the issue?
An unauthenticated remote attacker must send IPv4 or IPv6 UDP packets with both source and destination ports assigned to DHCP traffic through an affected device.
What is the impact of successful exploitation?
Successful exploitation allows an attacker to bypass configured endpoint group contracts on the affected device. The provided severity vector indicates integrity impact but no stated confidentiality or availability impact.