⚠️ Threat notice Cisco NX-OS Nexus 3000 and 9000 Switches

CVE-2026-76471 is a critical remote code execution vulnerability in the NX-API feature of Cisco NX-OS Software running on Nexus 3000 and 9000 Series Switches and UCS 6300 Series Fabric Interconnects. The vulnerability arises from insufficient input validation of data sent to the NX-API, enabling an unauthenticated remote attacker to execute arbitrary code with root privileges or cause process crashes leading to denial of service. Exploitation requires the NX-API feature to be enabled on Nexus switches, which is disabled by default, or valid low-privileged credentials on UCS 6300 devices. Cisco has released fixed software versions and a temporary Live Protect shield to mitigate the risk until updates can be applied. No workarounds exist. Cisco confirms no public exploitation or announcements of active attacks. Additional related critical vulnerabilities in NX-OS were disclosed concurrently in separate advisories.

Successful exploitation allows remote unauthenticated attackers to execute arbitrary code with root privileges on affected devices or cause denial of service through process crashes and device reloads. This can lead to full compromise of the network device and disruption of network operations. On UCS 6300 Series Fabric Interconnects, exploitation requires valid low-privileged user credentials, reducing the impact rating to high rather than critical. No public exploitation is currently known.

Cisco has released official software updates that fix this vulnerability. Customers should upgrade to the fixed software releases as soon as possible. There are no workarounds that fully mitigate this vulnerability. Cisco provides a Live Protect shield as a temporary mitigation to reduce risk until updates can be applied. Users should verify whether the NX-API feature is enabled and plan timely patching. For UCS 6300 Series Fabric Interconnects, ensure credential security to reduce risk. Refer to the Cisco Security Advisories for exact fixed software versions and upgrade instructions.