Cisco NX-OS Command Injection Vulnerability
CVE-2024-20399 is a security vulnerability in Cisco NX-OS, added to CISA KEV on July 2, 2024. Patch priority: Plan to patch.
What it is
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.
VulnCheck tracked exploitation 1 day before CISA's KEV listing. VulnCheck's broader catalog of in-the-wild exploitation evidence picked this up before it landed on CISA's formal list. Per-CVE fact about this entry; not a population claim about lead time in general.
Who's affected
Affects anyone with Cisco networking or security appliances on their network — typically a firewall, switch, or remote-access VPN. That device controls traffic to and from every workstation; exploitation can mean an attacker pivots inside the network without touching any user device.
What to do
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.
Insurance readiness
Your insurer will ask if this is patched.
Unpatched entries on CISA's Known Exploited Vulnerabilities list are exactly what cyber-insurance carrier questionnaires probe for, and knowing which controls they check is how you keep a renewal from stalling.
Get the free carrier questionnaire →Severity
CVSS base score: 6.0 — MEDIUM
Weakness classification: CWE-78
CISA due date
Federal deadline: July 23, 2024. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).
EPSS
EPSS score: 4.3% — higher than 90% of all scored CVEs.
EPSS estimates the probability of exploitation activity in the next 30 days. Every entry on this site is already confirmed exploited, so read it as relative urgency among the things you still have open, not as permission to wait.
Source
This entry comes from CISA's Known Exploited Vulnerabilities catalog, public US-Government data we pull daily. The plain-language framing and the what-to-do guidance above are ours. View the original entry on cisa.gov.