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

Summary

CVE-2026-20131 is a advisory from CISA-KEV. Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability Vendor: Cisco. Severity/Threat: critical. This item is marked as actively exploited. Source updated on 2026-03-25.

Product

Secure Firewall Management Center (FMC)

What to do

General, cautious steps (verify details in the official source):

• Prioritize patching or mitigation immediately (treat as actively risky).
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Check logs/telemetry for indicators of compromise and suspicious activity.
• Consider temporary hardening: restrict access, reduce attack surface, and monitor aggressively.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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