CVE-2026-20079

A vulnerability in the web interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to bypass authentication and execute script files on an affected device to obtain root access to the underlying operating system.  This vulnerability is due to an improper system process that is created at boot time. An attacker could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute a variety of scripts and commands that allow root access to the device. 

Score

CVSS 3.1 10.0 Critical

Status

Analyzed - psirt@cisco.com

Published

2026-03-04

Last modified

2026-09-16

Known exploited (CISA KEV)

since 2026-09-09, action due 2026-09-12: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Weaknesses

CWE-288

Affected products

• Cisco Secure Firewall Management Center Fmc (Cisco)
• Secure Firewall Management Center (Cisco)

References

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-onprem-fmc-authbypass-5JPp45V2
• http://seclists.org/fulldisclosure/2026/Aug/80
• https://blog.talosintelligence.com/fmc-ongoing-exploitation/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20079