Vulnerabilities · 179 days ago

Interlock Ransomware Exploits Cisco FMC Zero-Day for Root Access

Interlock exploited a zero-day in Cisco Secure Firewall Management Center (CVE-2026-20131) to execute arbitrary Java code as root. AWS threat intelligence observed exploitation beginning Jan 26, 2026, 36 days before Cisco’s March 4 disclosure. A misconfigured Interlock server exposed the group’s multi-stage toolkit and indicators.

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

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Vendor digest: Cisco

Part of the PlainSec briefing for 2026-03-25

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