Cisco Snort 3 resource consumption

Summaryinfo

A vulnerability identified as problematic has been detected in Cisco Cyber Vision, Secure Firewall Threat Defense Software and Snort 3. The affected element is an unknown function. Performing a manipulation results in resource consumption. This vulnerability is identified as CVE-2026-20356. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Cisco Cyber Vision, Secure Firewall Threat Defense Software and Snort 3 (affected version not known). This affects some unknown functionality. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as 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. This is going to have an impact on availability. The summary by CVE is:

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20356 are related to issues concerning uncontrolled resource consumption that are grouped under the Common Weakness Enumeration (CWE) Base CWE-400.

The advisory is shared at sec.cloudapps.cisco.com. This vulnerability is uniquely identified as CVE-2026-20356 since 10/08/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/21/2026). MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Cyber Vision
• Secure Firewall Threat Defense Software
• Snort 3

License

• commercial

Website

• Vendor: https://www.cisco.com/

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

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