Cisco Nexus 9000 Series Switches Silicon One 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. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n9k-s1-rce-EH8dEtr Security Impact Rating: Critical CVE: CVE-2026-20212
CSIRTS triage
- What
- Silicon One integration exposes TCP ports 43210 and 43211 in default L3 VRF, allowing unauthenticated remote code execution with root privileges.
- Who is affected
- Cisco Nexus 9000 Series Switches with Silicon One integration in default network configuration.
- Urgency
- Critical; unauthenticated remote root code execution with potential for device reload.
- Action
- Apply software updates from Cisco or implement network access controls to restrict access to ports 43210 and 43211.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch Nexus 9000 Series Switches
Get an email when a new Nexus 9000 Series Switches advisory drops — max one per day, one-click unsubscribe.
Details
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-20212 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- high[NEW] [high] Cisco Nexus: Vulnerability enables execution of arbitrary code with administrator privilegescert-bund
- criticalCVE-2026-20212: A vulnerability in the Silicon One integration for Cisco Nexus 9000 Series Switches could allo…nvd
- criticalCisco Advance Notification for Publication of September 2, 2026, Security Advisoriescisco-psirt
More from Cisco Security Advisories
- criticalCisco IOS XR Software Security Hardening Release: September 20262026-09-02
- criticalCisco Advance Notification for Publication of September 2, 2026, Security Advisories2026-09-02
- highCisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of …2026-09-02
- mediumCisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities2026-09-02
- criticalCisco Crosswork Security Hardening Release: August 20262026-08-21