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. Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the March 2026 release of the Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2026 Semiannual Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75736"].

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. 

Affected: CVE-2026-20079 - Cisco

CVE-2026-20079 - Cisco Secure Firewall Management Center Authentication Bypass to Root RCE

Product: Cisco Secure Firewall Management Center

Tested version: 10.0.1-1

CVE: CVE-2026-20079

PoC author: Arian Eidizadeh (CyberAuth)

Public PoC: https://github.com/CyberAuth/CVE-2026-20079

Technical write-up: https://banks.tools/writeups/cve-2026-20079-cisco-secure-fmc

The publicly documented authentication-bypass-to-root-RCE chain was independently reproduced against Cisco Secure FMC 10.0.1-1 with confirmed uid=0(root) execution.

The published Python implementation provides separate fingerprint, authentication-bypass check, bounded root-proof, exploit, verification, and cleanup functionality.

This work does not claim discovery of CVE-2026-20079 or independent discovery of the original exploit chain. The contribution is the independent reproduction and public PoC implementation.

References: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-onprem-fmc-authbypass-5JPp45V2 https://www.vulncheck.com/blog/cisco-fmc-auth-bypass-cve-2026-20079 https://github.com/CyberAuth/CVE-2026-20079 https://banks.tools/writeups/cve-2026-20079-cisco-secure-fmc _______________________________________________ Sent through the Full Disclosure mailing list https://nmap.org/mailman/listinfo/fulldisclosure Web Archives & RSS: https://seclists.org/fulldisclosure/

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.

Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Cisco Secure Firewall Management Center und Cisco Secure Firewall Threat Defense ausnutzen, um Root-Rechte zu erlangen, beliebigen Code mit Root-Rechten auszuführen, SQL-Injection durchzuführen und vertrauliche Daten offenzulegen sowie Daten zu manipulieren.