CVE-2026-20131 — Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability

Overview

Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management contain a deserialization of untrusted data vulnerability in the web-based management interface that could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device.

Vulnerability details

CVE ID

CVE-2026-20131

Vulnerability

Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability

Vendor

Cisco

Affected products

Cisco: Secure Firewall Management Center (FMC)

Severity

HIGH

Exploitation status

Actively exploited in the wild (CISA KEV)

EPSS score

27.6% probability of exploitation in 30 days · 98th percentile

Published

2026-03-19

Remediation guidance

CVE-2026-20131 is in CISA's Known Exploited Vulnerabilities (KEV) catalog — U.S. federal civilian agencies are required to remediate it under Binding Operational Directive 22-01. Treat it as a priority for every environment.

Apply the vendor's official security update for Cisco the affected product as soon as possible. Where a patch is unavailable, apply vendor mitigations or isolate/segment exposed systems.

FIRST EPSS estimates a 27.6% probability that CVE-2026-20131 will be exploited within the next 30 days (98th percentile of all CVEs) — useful for risk-based patch sequencing.

Hunt for indicators of compromise tied to this vulnerability and confirm logging/EDR coverage on affected assets.

Authoritative references

• NVD — National Vulnerability Database
• MITRE CVE Record
• CISA Known Exploited Vulnerabilities Catalog
• FIRST EPSS — Exploit Prediction Scoring

Related actively-exploited CVEs — Cisco