Exploited vulnerability · CISA KEV

Is CVE-2026-20131 exploited? Yes: in CISA KEV since 19 Mar 2026

Gociux · Cisco Secure Firewall Management Center (FMC) · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2026-20131, Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 19 Mar 2026, 15 days after it was published. It is known to be used in ransomware campaigns. It affects Cisco Secure Firewall Management Center (FMC), an internet-facing product of the kind attackers use for initial access. If you run it, CISA's required action is: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What it is

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.

What to do

1. Check whether you run it. Look for Secure Firewall Management Center (FMC) in your asset inventory, including appliances and cloud images. Stack check lists every exploited Cisco CVE at once.
2. Apply the fix. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 4 Mar 2026.
4. Get told next time. Email alerts when CISA adds a CVE for Cisco.

Other exploited CVEs in Secure Firewall Management Center (FMC)

• CVE-2026-20316: Cisco Secure Firewall Management Center Use of Hard-coded Password Vulnerability (29 Jul 2026)

References

• sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-
• nvd.nist.gov/vuln/detail/CVE-2026-20131

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in March 2026 · Cisco scorecard · act-now radar.