CRITICAL CISA KEV

CVE-2026-20131

CVSS v3

CRITICAL

EPSS Score

43.2 %

exploit probability, as of 2026-10-03

CISA KEV

Yes

known exploited

Exploitation

—

SSVC status

Description

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 al

CISA Known Exploited Vulnerability

Date Added: 2026-03-19
Patch Due Date: 2026-03-22
Ransomware Use: Known

Technical details

Published: 2026-03-04
Last Modified: 2026-03-25

Frequently asked questions

What is CVE-2026-20131?

Is CVE-2026-20131 actively exploited?

Yes. CVE-2026-20131 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-03-22.

What is the CVSS score for CVE-2026-20131?

CVE-2026-20131 has a CVSS v3 base score of 10 (CRITICAL severity).

Is CVE-2026-20131 affecting your environment?

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