Vulnerability · Published Sep 2, 2026 · Assigned by cisco
CVE-2026-20212Cisco Nexus 3000 and 9000 Series Switches Silicon One Hardware Abstraction Layer Remote Code Execution Vulnerability
Critical 9.8
In plain English
A critical-severity security flaw in Cisco NX-OS Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 58% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco NX-OS Software | 10.3(1)10.3(2)10.3(3)10.4(1)10.3(99w)10.3(3w)10.3(99x)10.3(3o) |
Weakness: CWE-1327 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H