CVE-2024-20399: Cisco NX-OS

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run Cisco NX-OS. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-07-02, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-07-23; treat that as the outer limit, not the target.
EPSS 4.3%, percentile 91: FIRST’s model estimates a 4.3% chance of exploitation activity in the next 30 days, higher than 91% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.

What it is

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 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

CISA’s summary

Cisco NX-OS contains a command injection vulnerability in the command line interface (CLI) that could allow an authenticated, local attacker to execute commands as root on the underlying operating system of an affected device.

Weakness type: CWE-78.

Product: Cisco NX-OS · Assigned by: cisco · Published: 2024-07-01

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
Cisco	Cisco NX-OS Software	8.2(5), 7.3(6)N1(1a), 7.3(5)D1(1), 8.4(2), 7.3(6)N1(1), 6.2(2), 8.4(3), 9.2(3), 7.0(3)I5(2), 8.2(1), 6.0(2)A8(7a), 7.0(3)I4(5)

Severity scores

Scored by	CVSS	Score	Vector
cisco	3.1	6 Medium	`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N`

Attack vector: local access needed
Attack complexity: low
Privileges required: high (admin)
User interaction: none
Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2024-07-02; federal due date 2024-07-23. Known ransomware use: Unknown.
CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
CISA SSVC assessment: exploitation active, automatable no, technical impact total.
FIRST EPSS (model of 2026-10-21): 4.31% probability of exploitation activity in the next 30 days; percentile 91.

Timeline

2024-07-01 — CVE record published by cisco
2024-07-02 — Added to CISA’s Known Exploited Vulnerabilities catalog
2024-07-23 — CISA remediation deadline for US federal agencies
2025-10-21 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Other references from the CVE record and advisory

sygnia.co sygnia.co

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