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Cisco · Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management

CVE-2026-20079

Cisco Secure Firewall Management Center Authentication Bypass Remote Code Execution Vulnerability

Exploited in attacks Critical 10.0 Attack chance: 88%
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What it is

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. 

CISA: Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management contain an authentication Bypass using an alternate path or channel vulnerability that 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.

What to do

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.

Deadline for US federal agencies: September 12, 2026

Added to the CISA list
September 9, 2026
Published
March 4, 2026
Severity
Critical 10.0 CVSS 3.1
Chance of attacks in the next 30 days (EPSS)
88% in the top 0.2% of all known vulnerabilities
Weakness
CWE-288
More details
NVD · CVE.org · CISA
All references (1)

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Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.