Skip to content
Fencer Vulns
critical 10.0

CVE-2026-20079 kev in the critical feed json

Cisco Secure Firewall Management Center Authentication Bypass Remote Code Execution Vulnerability

published 2026-03-04 8 mo ago modified 2026-09-16 53 d ago also EUVD-2026-9438

cvss
10.0
version 3.1, CNA
cisa kev
Exploited
added 2026-09-09
epss
88.7%
EPSS 88.7% chance of exploitation in 30 days, percentile 99.7%
public exploits
1
Metasploit, plus a Nuclei check

Summary

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. 

Patch / fix

cisa required action 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.

Timeline

  1. First public exploit (Metasploit exploit/linux/http/cisco_fmc_auth_bypass_rce)
  2. Published
  3. Added to CISA KEV
  4. CISA SSVC: exploitation active
  5. CISA patch deadline

Known exploited

Added
2 mo ago
Patch by
2026-09-12 (58 d ago)
Ransomware
Not known
Required action
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.
Vendor, product
Cisco, Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management
CISA name
Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
total
Assessed
1 mo ago

Exploit prediction

88.66% chance of exploitation in the next 30 days, higher than 99.7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Cisco Cisco Secure Firewall Management Center (FMC)

Classification

Weakness
  • CWE-288 Authentication Bypass Using an Alternate Path or Channel

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.