CVE-2026-20212: Cisco Nexus 3000 and 9000 Series Switches Silicon One Hardware Abstraction Layer Remote Code Execution Vulnerability
A vulnerability in the Silicon One integration for Cisco Nexus 9000 Series Switches could allow an unauthenticated, remote attacker to execute code with root privileges. This vulnerability exists because TCP ports 43210 and 43211 are accessible in the default Layer 3 (L3) virtual routing and forwarding (VRF). A successful exploit could allow the attacker to connect to an affected device and send crafted input that could be executed as code with root privileges. The exploitation of this vulnerability could also cause the S1HAL process to crash, which could cause the device to reload.
Affected Software
Event History
Frequently Asked Questions
Is authentication or prior access required to exploit this issue?
No. An unauthenticated remote attacker could exploit the vulnerability by connecting to an affected device and sending crafted input.
Are default network settings exposed?
Yes. The issue exists because TCP ports 43210 and 43211 are accessible in the default Layer 3 VRF.
What is the potential operational impact besides code execution?
In addition to code execution with root privileges, exploitation can crash the S1HAL process. A crash may cause the affected device to reload.