Executive Summary

CVE-2026-76485 is an improper input validation flaw in the VXLAN Operation, Administration, and Maintenance (NGOAM) feature of Cisco NX-OS, allowing an unauthenticated remote attacker to send crafted IP packets to an affected interface and achieve arbitrary code execution with root privileges or trigger a device-wide Denial-of-Service. Carrying a CVSS score of 9.8, a successful exploit against a data center or substation aggregation switch means loss of the switching fabric that carries process traffic, telemetry, and safety signaling.

Technical Exposure Breakdown

The defect sits in the NGOAM packet processing path. When the NGOAM feature is enabled, the device parses inbound IP traffic to support VXLAN overlay troubleshooting functions such as path tracing and connectivity verification. The vulnerability is rooted in insufficient validation of that IP traffic. An attacker who can reach any IP interface on the device can send malformed packets that the NGOAM handler mishandles, resulting in either memory corruption leading to code execution or a condition that crashes the process or the device.

Two conditions define the exposure. First, the NGOAM feature must be enabled. Switches running VXLAN overlays with OAM troubleshooting turned on are the primary population. Second, the attacker needs IP reachability to an interface on the box. Because the vector is unauthenticated and remote, no credentials, no session, and no prior foothold are required. The payload is a crafted packet, not an interactive exploit chain. That lowers the bar for both targeted intrusion and worm-style propagation across a flat fabric.

We are not asserting specific affected trains or fixed releases. The grounding data does not specify version ranges or patch availability, so operators should treat every NGOAM-enabled NX-OS switch as in scope until a vendor advisory maps their exact train.

OT Impact and Compliance Risk

In industrial environments, NX-OS switches rarely sit in isolation. They aggregate PLC traffic, historian feeds, SCADA polling, and increasingly VXLAN overlays used to segment control zones inside data center style process networks. Root on one of these switches means the attacker controls the forwarding plane. They can mirror traffic, inject frames, drop safety-relevant packets, or pivot into otherwise segmented VLANs. The DoS outcome is equally damaging in OT, where a switch reload during a process state transition can strand operators without visibility or control.

The IT assumption that a crashed switch is a recoverable outage does not hold here. In OT, a loss of switching during a running process can cascade into physical consequences. A remote unauthenticated root path through a core network device undermines the zone and conduit model that IEC 62443-3-3 depends on, because the conduit device itself becomes the pivot. For NERC CIP registered entities, a routable protocol path to an Electronic Access Control or Monitoring asset at this severity is a CIP-005 and CIP-007 concern that demands documented mitigation. Pipeline operators under TSA SD-02C should treat an unauthenticated RCE in a segmentation boundary device as a direct challenge to their network segmentation and access control objectives. Water utilities assessing risk under AWIA 2018 should log this against their network resilience findings.

Compensating Controls

Do not rely solely on an eventual vendor patch, and do not run active vulnerability scans against production NX-OS gear to confirm exposure. Aggressive scanning and crafted probe traffic against these devices can trigger the same faulty parsing path and brick or reload the switch you are trying to protect.

BreachSpider's AI analysis flags CVE-2026-76485 as a high-priority segmentation boundary risk for OT networks running Cisco VXLAN fabrics.

BreachSpider Intel

Track exposure, advisory revisions, and known exploited status for CVE-2026-76485 across your NX-OS fleet with BreachSpider continuous monitoring.