10.0 Critical Exploited · ransomware

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

Active exploitation observed

· CISA KEV catalogue

Required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware campaigns Known to be used

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 and versions

Product	Affected versions	Fixed in
Cisco Secure Firewall Management Center (FMC)	10.0.0	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.7	7.7.0 → 7.7.11	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.6	7.6.0 → 7.6.4	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.4	7.4.0 → 7.4.5	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.3	7.3.0 → 7.3.1.2	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.2	7.2.0 → 7.2.10.2	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.1	7.1.0 → 7.1.0.3	No fix stated
Cisco Secure Firewall Management Center (FMC) 7.0	7.0.0 → 7.0.8.1	No fix stated
Cisco Secure Firewall Management Center (FMC) 6.4	6.4.0.13 → 6.4.0.18	No fix stated