Cisco Secure Firewall Threat Defense up to 7.6.4 Snort 2 Detection Engine resource consumption

Summaryinfo

A vulnerability identified as critical has been detected in Cisco Secure Firewall Threat Defense. Affected by this vulnerability is an unknown functionality of the component Snort 2 Detection Engine. This manipulation causes resource consumption. The identification of this vulnerability is CVE-2026-20290. It is possible to initiate the attack remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Cisco Secure Firewall Threat Defense and classified as critical. Affected by this vulnerability is some unknown functionality of the component Snort 2 Detection Engine. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

A vulnerability in SSL/TLS certificate parsing in the Snort 2 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 2 Detection Engine to restart. This vulnerability is due to incomplete validation of the SSL certificate. An attacker could exploit this vulnerability by sending a crafted SSL connection setup request to be parsed by Snort 2. A successful exploit could allow the attacker to cause the Snort 2 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.

It is possible to read the advisory at sec.cloudapps.cisco.com. This vulnerability is known as CVE-2026-20290 since 10/08/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/16/2026). The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Secure Firewall Threat Defense

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
• 7.2.4
• 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
• 7.2.10.2
• 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
• 7.4.7
• 7.6.0
• 7.6.1
• 7.6.2
• 7.6.2.1
• 7.6.4

License

• commercial

Website

• Vendor: https://www.cisco.com/

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