CVE-2026-20079 | defend.network

What is 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.

CVSS10 NVD 3.1

SeverityCRITICAL

Exploitation In the wild In CISA KEV

EPSS88% · P100

Triage statusActive Exploit

ActionPatch immediately

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CWECWE-288

NVD published2026-03-04

NVD last modified2026-09-16

Timeline

2026-03-04Published to the U.S. National Vulnerability Database (NVD)
2026-09-09Added to the CISA Known Exploited Vulnerabilities (KEV) catalog
2026-09-10First covered in a defend.network daily briefing
2026-09-12CISA federal remediation deadline (BOD 22-01)
2026-09-16NVD record last updated

CISA Known Exploited Vulnerability

Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability

Added to KEV2026-09-09

Federal patch deadline2026-09-12

Known ransomware useUnknown

Affected product

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

Remediation Steps

Apply the vendor security update for Cisco Secure Firewall Management Center as a priority.
Restrict network exposure of the affected service to trusted sources until patched.
Review logs and detections for indicators of exploitation.
Confirm fixed versions against the official vendor advisory before deploying.

References

Referenced in our briefings & reports

Vulnerability Priority Report – Week 1 of October 2026 (October 5 – 11)
Vulnerability Priority Report – Week 4 of September 2026 (September 28 – October 4)
Vulnerability Priority Report – Week 3 of September 2026 (September 21 – 27)
Vulnerability Priority Report – Week 2 of September 2026 (September 14 – 20)
Vulnerability Priority Report – Week 1 of September 2026 (September 7 – 13)
Hardware attack breaks Intel/AMD confidential computing; Gitea RCE exploited across six countries (2026-09-15)
Cisco FMC actively exploited; BlueMoon exploit kit chains Chrome & Windows; AI tokens bypass MFA (2026-09-10)

Browse all tracked CVEs in the defend.network CVE database →

🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.