Unauthenticated root code execution via exposed S1HAL ports
Published Sep 2, 2026 · Updated Sep 3, 2026
Remote code execution in Cisco NX-OS Software allows remote attackers to run code as root through exposed Silicon One service ports. The Silicon One integration exposes TCP ports 43210 and 43211 in the default L3 VRF and executes crafted input received through them. No authentication is required; successful exploitation grants full device control, while malformed input can crash S1HAL and reload the switch.
Summary
What happened
Remote code execution in Cisco NX-OS Software allows remote attackers to run code as root through exposed Silicon One service ports. The Silicon One integration exposes TCP ports 43210 and 43211 in the default L3 VRF and executes crafted input received through them. No authentication is required; successful exploitation grants full device control, while malformed input can crash S1HAL and reload the switch.
The record
- CVE
- CVE-2026-20212
- Published
- Sep 2, 2026
- Updated
- Sep 3, 2026
- Vendor
- ClamAV
- Product
- Cisco NX-OS Software
- Classifications
- CWE-1327, CAPEC-1, T1210
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 2, 2026CVE publishedPublication date reported by the CVE source.
- Sep 3, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.3(1)
- Affected versionversion=10.3(2)
- Affected versionversion=10.3(3)
- Affected versionversion=10.3(3o)
- Affected versionversion=10.3(3p)
- Affected versionversion=10.3(3q)
- Affected versionversion=10.3(3r)
- Affected versionversion=10.3(3w)
- Affected versionversion=10.3(3x)
- Affected versionversion=10.3(4)
- Affected versionversion=10.3(4a)
- Affected versionversion=10.3(4g)
- Affected versionversion=10.3(4h)
- Affected versionversion=10.3(5)
- Affected versionversion=10.3(6)
- Affected versionversion=10.3(7)
- Affected versionversion=10.3(8)
- Affected versionversion=10.3(9)
- Affected versionversion=10.3(99w)
- Affected versionversion=10.3(99x)
- Affected versionversion=10.4(1)
- Affected versionversion=10.4(2)
- Affected versionversion=10.4(3)
- Affected versionversion=10.4(4)
- Affected versionversion=10.4(4g)
- Affected versionversion=10.4(5)
- Affected versionversion=10.4(6)
- Affected versionversion=10.4(7)
- Affected versionversion=10.5(1)
- Affected versionversion=10.5(2)
- Affected versionversion=10.5(3)
- Affected versionversion=10.5(3e)
- Affected versionversion=10.5(3o)
- Affected versionversion=10.5(3p)
- Affected versionversion=10.5(3s)
- Affected versionversion=10.5(3t)
- Affected versionversion=10.5(4)
- Affected versionversion=10.5(5)
- Affected versionversion=10.6(1)
- Affected versionversion=10.6(1s)
- Affected versionversion=10.6(2)
- Affected versionversion=10.6(2n)
- Affected versionversion=10.6(2s)
- Affected versionversion=10.6(3)
- Affected versionversion=10.6(3s)
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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