CVE-2026-20212

Cisco Nexus 3000 and 9000 Series Switches Silicon One Hardware Abstraction Layer Remote Code Execution Vulnerability

Severity
Critical 9.8
CVSS 3.1
Exploited
Not listed
EPSS
0.005
43.7th percentile
Discovered by
Third party
Vendor-published field
Published
Sep 2, 2026
Assigned by cisco

Description

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.

Weakness: CWE-1327

Affected products

Vendor Product Category Matched by
Cisco Cisco NX-OS Software Routing & Switching cna-assigner
Vendor-reported products (1)
  • Cisco · Cisco NX-OS Software

Something wrong here?