---
id: "CVE-2026-20131"
kind: "vulnerability"
aliases: ["CVE-2026-20131"]
title: "A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software\u2026"
severity: "critical"
cvss: 10.0
epss: null
exploited: true
status: "open"
category: "vendor"
products: [{"name": "Cisco Secure Firewall Management Center (FMC)", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 6.4.0.13", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 6.4.0.14", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 6.4.0.15", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 6.4.0.16", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 6.4.0.17", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 6.4.0.18", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.0", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.0.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.1.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.2", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.2.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.3", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.4", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.5", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.6", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.6.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.6.2", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.6.3", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.7", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.8", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.0.8.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.1.0", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.1.0.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.1.0.2", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.1.0.3", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.0", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.0.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.2", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.3", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.3.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.4", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.4.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.5", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.5.1", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.5.2", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.6", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.7", "ecosystem": "vendor"}, {"name": "cisco secure firewall management center", "fixed": [], "affected": "= 7.2.8", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["cisco", "exploited", "firewall-management", "fmc", "ransomware", "security-cloud-control", "vendor"]
not_affected_if: ["unknown"]
published_at: "2026-03-04T18:16:27+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T23:44:51+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-20131", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20131", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software…

Cisco Secure Firewall Management Center (FMC) and Cisco Security Cloud Control firewall management contain a deserialization flaw in the web management interface. An unauthenticated remote attacker can run arbitrary Java code as root on the affected device.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Cisco Secure Firewall Management Center (FMC) affected ? fixed ?
- vendor:cisco secure firewall management center affected = 6.4.0.13 fixed ?
- vendor:cisco secure firewall management center affected = 6.4.0.14 fixed ?
- vendor:cisco secure firewall management center affected = 6.4.0.15 fixed ?
- vendor:cisco secure firewall management center affected = 6.4.0.16 fixed ?
- vendor:cisco secure firewall management center affected = 6.4.0.17 fixed ?
- vendor:cisco secure firewall management center affected = 6.4.0.18 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.0 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.0.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.1.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.2 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.2.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.3 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.4 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.5 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.6 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.6.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.6.2 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.6.3 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.7 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.8 fixed ?
- vendor:cisco secure firewall management center affected = 7.0.8.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.1.0 fixed ?
- vendor:cisco secure firewall management center affected = 7.1.0.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.1.0.2 fixed ?
- vendor:cisco secure firewall management center affected = 7.1.0.3 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.0 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.0.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.2 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.3 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.3.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.4 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.4.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.5 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.5.1 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.5.2 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.6 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.7 fixed ?
- vendor:cisco secure firewall management center affected = 7.2.8 fixed ?

## Fix

Apply the vendor mitigations or fixed release from Cisco's advisory; the sources do not name a version. If mitigations are unavailable, CISA says to discontinue use of the product.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-20131
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-20131

## From the sources

A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device.

This vulnerability is due to insecure deserialization of a user-supplied Java byte stream. An attacker could exploit this vulnerability by sending a crafted serialized Java object to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the device and elevate privileges to root.
Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_