CVE-2026-20212: Binding to an Unrestricted IP Address in Cisco Cisco NX-OS Software
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.
CVSS v3.1
Score 9.8critical
Affected software
Cisco
Cisco NX-OS Software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability arises because TCP ports 43210 and 43211 are accessible by default in the Layer 3 virtual routing and forwarding (VRF) context on Cisco Nexus 9000 Series Switches using the Silicon One integration. An unauthenticated remote attacker can connect to these ports and send crafted input that is executed as code with root privileges. Additionally, exploitation may crash the S1HAL process, leading to device reloads. The CVSS 3.1 base score is 9.8, indicating critical severity with network attack vector, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.
Potential Impact
An unauthenticated remote attacker can gain root code execution on affected devices, compromising confidentiality, integrity, and availability. The vulnerability also risks causing the S1HAL process to crash, which may lead to device reloads and potential network disruption.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround information is provided in the available data. Until a patch is available, restrict network access to TCP ports 43210 and 43211 if possible and monitor for suspicious activity targeting these ports.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisco
- Date Reserved
- 2025-10-08T11:59:15.398Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a9850dcacd9273b4977c50f
Added to database: 09/02/2026, 16:37:48 UTC
Last enriched: 09/07/2026, 13:19:26 UTC
Last updated: 10/17/2026, 18:48:17 UTC
Views: 114
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.