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CVE-2026-20016 Cisco CVE debrief

A vulnerability in the Cisco FXOS Software CLI feature for Cisco Secure Firewall ASA Software and Secure FTD Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system with root-level privileges. To exploit this vulnerability, the attacker must have valid administrative credentials on an affected device. This vulnerability is due to insufficient input validation of user-supplied command arguments. An attacker could exploit this vulnerability by submitting crafted input for specific CLI commands. A successful exploit could allow the attacker to execute commands on the underlying operating system with root-level privileges.

Vendor
Cisco
Product
Cisco Secure Firewall Threat Defense (FTD) Software
CVSS
MEDIUM 6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-04
Original CVE updated
2026-08-11
Advisory published
2026-03-04
Advisory updated
2026-08-11

Who should care

Administrators and users of Cisco Secure Firewall ASA Software and Secure FTD Software should be aware of this vulnerability and take necessary actions to mitigate it.

Technical summary

The vulnerability exists in the Cisco FXOS Software CLI feature for Cisco Secure Firewall ASA Software and Secure FTD Software. It allows an authenticated, local attacker to execute arbitrary commands on the underlying operating system with root-level privileges. The vulnerability is caused by insufficient input validation of user-supplied command arguments.

Defensive priority

high

Recommended defensive actions

  • Apply patches or updates as recommended by the vendor [ref-4].
  • Restrict access to the CLI feature to only necessary personnel.
  • Monitor system logs for suspicious activity.

Evidence notes

CVE-2026-20016 has a CVSS score of 6 and is classified as MEDIUM severity. The vulnerability was published on March 4, 2026, and last modified on June 5, 2026.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-20016 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-20016

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-20016 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-20016

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.