Risk Letters

Exploited vulnerability

CVE-2026-20131

TLP:CLEAR

Cisco Secure Firewall Management Center (FMC) Software and Cisco Security Cloud Control (SCC) Firewall Management Deserialization of Untrusted Data Vulnerability

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.

Facts

  • Vendor: Cisco
  • Product: Secure Firewall Management Center (FMC)
  • CVSS: 10
  • EPSS (probability of exploitation within 30 days): 44.4 %
  • On CISA's Known Exploited Vulnerabilities list since: 19 March 2026
  • First known exploitation: 19 March 2026
  • Used in ransomware campaigns (per CISA): Yes
  • CISA's deadline for US federal agencies: 22 March 2026
  • Weakness: CWE-502
  • First seen by Risk Letters: 20 March 2026

Members see which Nordic sectors the flaw hits, and what to do about it.

Get the full brief

Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD