Critical Cisco Nexus 9000 Flaw Lets Unauthenticated Remote Attackers Run Code as Root

Critical Cisco Nexus 9000 Flaw Lets Unauthenticated Remote Attackers Run Code as Root Swati KhandelwalSep 03, 2026Vulnerability / Network Security Cisco has released patches to address a critical security flaw affecting 10 Silicon One-based Nexus 9000 switches that could allow an unauthenticated, remote attacker to execute code as root, alongside an IOS XR hardening release bundling 7 umbrella CVEs, 2 of which are rated 9.8, with no workaround for any IOS XR version. The Nexus vulnerability, tracked as CVE-2026-20212 (CVSS score: 9.8), is a case of binding to an unrestricted IP address that leaves TCP ports 43210 and 43211 reachable in the default Layer 3 virtual routing and forwarding (VRF) instance. An attacker who can reach a switch's address on…