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PatchSiren cyber security CVE debrief

CVE-2024-20399 Cisco CVE debrief

CVE-2024-20399 is a Cisco NX-OS command injection vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2024-07-02. That KEV listing means defenders should treat it as urgently actionable, even though the supplied corpus does not include a CVSS score or the full vendor-advisory technical details. Cisco’s official advisory and the NVD entry are the primary public references in the provided sources.

Vendor
Cisco
Product
NX-OS
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2024-07-02
Original CVE updated
2024-07-02
Advisory published
2024-07-02
Advisory updated
2024-07-02

Who should care

Cisco NX-OS administrators, network operations teams, security operations teams, vulnerability management owners, and any organization that relies on Cisco NX-OS in production or exposed management environments.

Technical summary

The supplied sources identify the issue as a command injection vulnerability in Cisco NX-OS and confirm it is known to be exploited in the wild via CISA’s KEV catalog. The provided corpus does not include affected-version ranges, attack prerequisites, impact depth, or a CVSS score, so those specifics should be taken only from the vendor advisory and NVD record linked in the resources.

Defensive priority

High. CISA KEV inclusion and the required mitigation deadline indicate this vulnerability should be prioritized immediately in inventory, exposure review, and remediation planning.

Recommended defensive actions

  • Review Cisco’s official advisory for mitigation and upgrade guidance using the linked vendor notice.
  • If Cisco states that mitigations are unavailable or incomplete, follow CISA guidance to discontinue use of the product or remove exposure where possible.
  • Identify all Cisco NX-OS assets in your environment, including management interfaces and any externally reachable instances.
  • Prioritize patching or mitigation for internet-facing, management-plane, and high-privilege network devices first.
  • Monitor for signs of exploitation or suspicious configuration changes on affected Cisco NX-OS systems.
  • Validate remediation status against the CISA KEV due date and track closure in vulnerability management records.

Evidence notes

Evidence in the supplied corpus is limited to the CISA KEV entry and metadata, which explicitly names the vulnerability as a Cisco NX-OS command injection issue and marks it as known exploited. The corpus also points to Cisco’s security advisory and the NVD detail page, but no advisory text, affected versions, or CVSS values were included here. Timing context comes from the provided CVE and KEV dates: published and added to KEV on 2024-07-02, with a KEV due date of 2024-07-23.

Official resources

Publicly listed by CISA in the Known Exploited Vulnerabilities catalog on 2024-07-02. CISA set the remediation due date to 2024-07-23. The provided corpus does not include additional disclosure timing beyond those official dates.