What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2026-03-19
• EPSS: 44.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-04 · updated 2026-06-17
• Weakness: CWE-502

Description

A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device. This vulnerability is due to insecure deserialization of a user-supplied Java byte stream. An attacker could exploit this vulnerability by sending a crafted serialized Java object to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the device and elevate privileges to root. Note: If the FMC management interface does not have public internet access, the attack surface that is associated with this vulnerability is reduced.

Affected products

• Cisco Firepower Management Center: 6.4.0.13, 6.4.0.14, 6.4.0.15, 6.4.0.16, 6.4.0.17, 6.4.0.18 (+65)

References

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-rce-NKhnULJh
• https://aws.amazon.com/blogs/security/amazon-threat-intelligence-teams-identify-interlock-ransomware-campaign-targeting-enterprise-firewalls/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20131

Get alerted when CVE-2026-20131 or the next vulnerability affects your stack