Raw vector
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:NSummary
CVE-2024-20399 is a medium-severity OS Command Injection (CWE-78) vulnerability in Cisco Nx-Os. Its CVSS base score is 6.0 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 10% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
A vulnerability in the CLI of Cisco NX-OS Software allows an authenticated user possessing Administrator credentials to execute arbitrary commands as root on the underlying operating system. The issue stems from insufficient validation of arguments supplied to specific configuration CLI commands and is tracked as CWE-78. It affects multiple Cisco Nexus switch platforms running vulnerable NX-OS releases, although the listed Nexus 3000, 7000 (8.1(1) and later), and 9000 standalone devices already permit administrative users to reach the underlying OS via the bash-shell feature and therefore receive no additional capability from this flaw. The CVSS 3.1 base score is 6.0 with the vector AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N.
An attacker must already hold Administrator credentials on an affected device. By supplying crafted input to an impacted configuration command, the attacker can run arbitrary commands on the host OS with root privileges. On devices that do not expose the bash-shell feature by default, this constitutes an escalation from CLI-restricted administrative access to full root control of the underlying system.
The Cisco Security Advisory cisco-sa-nxos-cmd-injection-xD9OhyOP describes the vulnerability and provides fixed software releases. CISA has added the CVE to its Known Exploited Vulnerabilities catalog, indicating confirmed in-the-wild use.
Public reporting attributes exploitation of the issue to the China-nexus threat group Velvet Ant. The EPSS score rose from a low baseline to a peak of 0.0225 on 2024-07-03 shortly after disclosure before receding to the current value of 0.0066, indicating a transient increase in observed exploitation interest following publication.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2024-18114
Vulnerability Data
A vulnerability in the CLI of Cisco NX-OS Software could allow an authenticated user in possession of Administrator credentials to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient…
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validation of arguments that are passed to specific configuration CLI commands. An attacker could exploit this vulnerability by including crafted input as the argument of an affected configuration CLI command. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privileges of root. Note: To successfully exploit this vulnerability on a Cisco NX-OS device, an attacker must have Administrator credentials. The following Cisco devices already allow administrative users to access the underlying operating system through the bash-shell feature, so, for these devices, this vulnerability does not grant any additional privileges: Nexus 3000 Series Switches Nexus 7000 Series Switches that are running Cisco NX-OS Software releases 8.1(1) and later Nexus 9000 Series Switches in standalone NX-OS mode
- CWE(s)
- KEV Date Added
- 02 July 2024
Related Threats
Threat-Actor AttributionAI
MITRE ATT&CK Enterprise Techniques
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Affected Assets
Mitigating Controls
Control response
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect command sanitization during development.
Input validation directly neutralizes or rejects special characters that would otherwise alter OS command structure.
Least privilege reduces the permissions available to any process that could be subverted by injected commands.
Least functionality restricts available OS commands and interpreters, limiting the blast radius of injection.
Secure engineering principles require proper neutralization of untrusted input before command construction.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.
Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.