Vulnerabilities & Exploits · Ransomware

Interlock Compromises Enterprise Firewalls via Cisco FMC Zero-Day

Amazon/AWS threat intelligence observed exploitation beginning January 26, 2026 — 36 days before Cisco publicly disclosed the vulnerability. A misconfigured Interlock staging server exposed the group's multi-stage toolkit and indicators of compromise.

9 sources · Mar 20

CVE-2026-20131

NVD KEV

Known exploited · CISA KEV

CVSS 10 CRITICAL: a vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could… Known ransomware campaign use. EPSS 33% (98th percentile).

CISA federal remediation date Mar 22

Timeline

Sources

Vendor digest: Cisco

Part of the PlainSec briefing for 2026-03-19

Every edition of this story: Interlock Compromises Enterprise Firewalls via Cisco FMC Zero-Day

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