Deserialization of Untrusted Data in Cisco Firewall Threat Defense (FTD) and Cisco Secure Firewall Management Center (formerly Firepower Management Center, FMC) - CVE-2026-20131
Published: March 6, 2026 / Updated: March 19, 2026
Vulnerability identifier: #VU123617
CSH Severity: Critical
CVSS v4: 10 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H]
CVE-ID: CVE-2026-20131
CWE-ID: CWE-502
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to insecure input validation when processing serialized data in the web-based management interface. A remote non-authenticated attacker can send specially crafted serialized Java object to the web-based management interface of an affected device and execute arbitrary code on the target system with root privileges.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Affected software
Cisco Firewall Threat Defense (FTD)
Cisco Secure Firewall Management Center (formerly Firepower Management Center, FMC)
Cisco Secure Firewall Management Center (formerly Firepower Management Center, FMC)
How to mitigate CVE-2026-20131
Install updates from vendor's website.
Cisco Firewall Threat Defense (FTD) - addressed in versions 7.0.9, 7.2.11, 7.4.6, 7.6.5, 7.7.12, 10.0.1
Cisco Secure Firewall Management Center (formerly Firepower Management Center, FMC) - addressed in versions 7.0.9, 7.2.11, 7.4.6, 7.6.5, 7.7.12, 10.0.1
Cisco Secure Firewall Management Center (formerly Firepower Management Center, FMC) - addressed in versions 7.0.9, 7.2.11, 7.4.6, 7.6.5, 7.7.12, 10.0.1