Vulnerability in Cisco Nx-Os Software
CVE-2026-20212
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.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Cisco Nx-os Software — versions 10.3(1), 10.3(2), 10.3(3)
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-20212?
- CVE-2026-20212 is a critical-severity vulnerability in Cisco Nx-Os Software, classified under CWE-1327. CVSS score: 9.8/10. Published 2026-09-02.
- How severe is CVE-2026-20212?
- Critical severity. CVSS v3 base score is 9.8 out of 10.