---
id: CVE-2026-20242
title: "A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary commands as root on an affected device.\r\n\r\nThis v…"
summary: "A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary commands as root on an affected device.\r\n\r\nThis v…"
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-502
vendor: Cisco
product: Cisco Secure Firewall Management Center (FMC)
affected:
  - secure_firewall_management_center_fmc 7.0.0
  - secure_firewall_management_center_fmc 7.0.0.1
  - secure_firewall_management_center_fmc 7.0.1
  - secure_firewall_management_center_fmc 7.0.1.1
  - secure_firewall_management_center_fmc 7.0.2
  - secure_firewall_management_center_fmc 7.2.0
  - secure_firewall_management_center_fmc 7.0.2.1
  - secure_firewall_management_center_fmc 7.0.3
  - secure_firewall_management_center_fmc 7.2.0.1
  - secure_firewall_management_center_fmc 7.0.4
  - secure_firewall_management_center_fmc 7.2.1
  - secure_firewall_management_center_fmc 7.0.5
  - secure_firewall_management_center_fmc 7.3.0
  - secure_firewall_management_center_fmc 7.2.2
  - secure_firewall_management_center_fmc 7.3.1
  - secure_firewall_management_center_fmc 7.2.3
  - secure_firewall_management_center_fmc 7.2.3.1
  - secure_firewall_management_center_fmc 7.2.4
  - secure_firewall_management_center_fmc 7.0.6
  - secure_firewall_management_center_fmc 7.2.4.1
  - secure_firewall_management_center_fmc 7.2.5
  - secure_firewall_management_center_fmc 7.3.1.1
  - secure_firewall_management_center_fmc 7.4.0
  - secure_firewall_management_center_fmc 7.0.6.1
  - secure_firewall_management_center_fmc 7.2.5.1
  - secure_firewall_management_center_fmc 7.4.1
  - secure_firewall_management_center_fmc 7.2.6
  - secure_firewall_management_center_fmc 7.4.1.1
  - secure_firewall_management_center_fmc 7.0.6.2
  - secure_firewall_management_center_fmc 7.2.7
  - secure_firewall_management_center_fmc 7.2.5.2
  - secure_firewall_management_center_fmc 7.3.1.2
  - secure_firewall_management_center_fmc 7.2.8
  - secure_firewall_management_center_fmc 7.6.0
  - secure_firewall_management_center_fmc 7.4.2
  - secure_firewall_management_center_fmc 7.2.8.1
  - secure_firewall_management_center_fmc 7.0.6.3
  - secure_firewall_management_center_fmc 7.4.2.1
  - secure_firewall_management_center_fmc 7.2.9
  - secure_firewall_management_center_fmc 7.0.7
  - secure_firewall_management_center_fmc 7.7.0
  - secure_firewall_management_center_fmc 7.4.2.2
  - secure_firewall_management_center_fmc 7.2.10
  - secure_firewall_management_center_fmc 7.6.1
  - secure_firewall_management_center_fmc 7.4.2.3
  - secure_firewall_management_center_fmc 7.0.8
  - secure_firewall_management_center_fmc 7.6.2
  - secure_firewall_management_center_fmc 7.7.10
  - secure_firewall_management_center_fmc 7.2.10.1
  - secure_firewall_management_center_fmc 7.0.8.1
published: '2026-09-16'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T04:17:34.083'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20242'
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-javarce-y2NypXwk
    label: psirt@cisco.com
  - url: 'https://software.cisco.com'
tags:
  - nvd
  - cve.org
  - csaf
  - vendor-advisory
  - cisco
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-09-17T14:55:25.547804Z'
ingestedAt: '2026-09-16T16:37:52.198Z'
epss: 0.00639
epssPercentile: 0.48432
---

## Overview

A vulnerability in the External Database Access feature of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary commands as root on an affected device.

This vulnerability is due to insecure deserialization of a user-supplied Java byte stream from a host that is configured in the external database access list. An attacker could exploit this vulnerability by sending a crafted, serialized Java byte stream to a specific TCP port of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the device and elevate privileges to root.
Notes:

This vulnerability can be exploited only by an attacker who has control of a host in the external database access list.
If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **cisco-sa-fmc-javarce-y2NypXwk** · Cisco · affected: Cisco Secure Firewall Management Center (FMC) Appliances · updated 2026-09-16 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-javarce-y2NypXwk)