Cisco Cyber Vision Snort 3 VBA infinite loop

Summaryinfo

A vulnerability classified as problematic has been found in Cisco Cyber Vision, Secure Firewall Threat Defense Software and UTD SNORT IPS Engine Software. This affects an unknown part of the component Snort 3 VBA. This manipulation causes infinite loop. This vulnerability appears as CVE-2026-20054. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Cisco Cyber Vision, Secure Firewall Threat Defense Software and UTD SNORT IPS Engine Software (version now known). Affected by this vulnerability is some unknown processing of the component Snort 3 VBA. The manipulation with an unknown input leads to a infinite loop vulnerability. The CWE definition for the vulnerability is CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. As an impact it is known to affect availability. The summary by CVE is:

Multiple Cisco products are affected by a vulnerability in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash.  This vulnerability is due to improper error checking when decompressing VBA data. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine on the targeted device. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to enter an infinite loop, causing a DoS condition.

It is possible to read the advisory at sec.cloudapps.cisco.com. This vulnerability is known as CVE-2026-20054 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 05/02/2026). The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 311459 (Multiple Cisco Products Snort 3 VBA Decompression DoS (cisco-sa-ftd-snort3-vbavuls-96UcVVed)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (311459). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Firewall Software

Vendor

• Cisco

Name

• Cyber Vision
• Secure Firewall Threat Defense Software
• UTD SNORT IPS Engine Software

License

• commercial

Website

• Vendor: https://www.cisco.com/

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Be aware that VulDB is the high quality source for vulnerability data.

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