Cisco Secure Firewall Management Center up to 10.0.0 Web-based Management Interface deserialization

Summaryinfo

A vulnerability has been found in Cisco Secure Firewall Management Center and classified as very critical. This affects an unknown function of the component Web-based Management Interface. The manipulation leads to deserialization. This vulnerability is referenced as CVE-2026-20131. Remote exploitation of the attack is possible. Furthermore, an exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Cisco Secure Firewall Management Center. It has been rated as very critical. This issue affects an unknown part of the component Web-based Management Interface. The manipulation with an unknown input leads to a deserialization vulnerability. Using CWE to declare the problem leads to CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at sec.cloudapps.cisco.com. The identification of this vulnerability is CVE-2026-20131 since 10/08/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are unknown but an exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 03/26/2026).

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 302914 (Cisco Secure Firewall Management Center Software RCE (cisco-sa-fmc-rce-NKhnULJh)), which helps to determine the existence of the flaw in a target environment. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 03/19/2026 with a due date of 03/22/2026:

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

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (302914), EUVD (EUVD-2026-9444) and CERT Bund (WID-SEC-2026-0610). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Cisco Secure Firewall Management Center
• Cisco Secure Firewall Threat Defense

Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Secure Firewall Management Center

Version

• 6.4.0.13
• 6.4.0.14
• 6.4.0.15
• 6.4.0.16
• 6.4.0.17
• 6.4.0.18
• 7.0.0
• 7.0.0.1
• 7.0.1
• 7.0.1.1
• 7.0.2
• 7.0.2.1
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.6.1
• 7.0.6.2
• 7.0.6.3
• 7.0.7
• 7.0.8
• 7.0.8.1
• 7.1.0
• 7.1.0.1
• 7.1.0.2
• 7.1.0.3
• 7.2.0
• 7.2.0.1
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.3.1
• 7.2.4
• 7.2.4.1
• 7.2.5
• 7.2.5.1
• 7.2.5.2
• 7.2.6
• 7.2.7
• 7.2.8
• 7.2.8.1
• 7.2.9
• 7.2.10
• 7.2.10.1
• 7.2.10.2
• 7.3.0
• 7.3.1
• 7.3.1.1
• 7.3.1.2
• 7.4.0
• 7.4.1
• 7.4.1.1
• 7.4.2
• 7.4.2.1
• 7.4.2.2
• 7.4.2.3
• 7.4.2.4
• 7.4.3
• 7.4.4
• 7.4.5
• 7.6.0
• 7.6.1
• 7.6.2
• 7.6.2.1
• 7.6.3
• 7.6.4
• 7.7.0
• 7.7.10
• 7.7.10.1
• 7.7.11
• 10.0.0

License

• commercial

Website

• Vendor: https://www.cisco.com/

CPE 2.3info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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