Cisco Secure Firewall Management Center up to 10.0.1 deserialization

Summaryinfo

A vulnerability described as very critical has been identified in Cisco Secure Firewall Management Center. Affected by this vulnerability is an unknown functionality. Such manipulation leads to deserialization. This vulnerability is listed as CVE-2026-20340. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in Cisco Secure Firewall Management Center. Affected by this issue is an unknown code block. 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. CVE summarizes:

A vulnerability in Cisco Secure FMC Software could allow an authenticated, remote attacker to execute arbitrary commands at the root privilege level. This vulnerability is due to unsecured deserialization of web-management user-controlled data. An attacker could exploit this vulnerability by authenticating to the device and sending a crafted HTTP payload. A successful exploit could allow the attacker to save the crafted payload and then execute it on the underlying operating system as root. To exploit this vulnerability, the attacker must have valid credentials for a user account with at least the role of Security Analyst (read-only).

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability is handled as CVE-2026-20340 since 10/08/2025. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/16/2026).

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Secure Firewall Management Center

Version

• 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
• 7.0.9
• 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
• 7.2.11
• 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
• 7.4.6
• 7.4.7
• 7.6.0
• 7.6.1
• 7.6.2
• 7.6.2.1
• 7.6.3
• 7.6.4
• 7.6.5
• 7.7.0
• 7.7.10
• 7.7.10.1
• 7.7.11
• 7.7.12
• 10.0.0
• 10.0.1

License

• commercial

Website

• Vendor: https://www.cisco.com/

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