CVE-2026-20053
Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Heap Overflow Denial of Service Vulnerability
Description
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 range checking when decompressing VBA data, which is user controlled. 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 an overflow of heap data, which could cause a DoS condition.
Weakness: CWE-122
Affected products
| Vendor | Product | Category | Matched by |
|---|---|---|---|
| Cisco | Cisco Cyber Vision | OT / IoT Security | cna-assigner |
| Cisco | Cisco Firepower Threat Defense (FTD) Check your version | Firewall / NGFW | cna-assigner |
| Cisco | Cisco UTD SNORT IPS Engine | Threat Detection & Sandbox | cna-assigner |
Vendor-reported products (3)
- Cisco · Cisco Cyber Vision
- Cisco · Cisco Secure Firewall Threat Defense (FTD) Software
- Cisco · Cisco UTD SNORT IPS Engine Software
Vendor advisory
cisco-sa-ftd-snort3-vbavuls-96UcVVed
Multiple Cisco Products Snort 3 Visual Basic for Applications Denial of Service Vulnerabilities
Cisco’s rating: Medium (advisory CVSS 5.8) · Published Mar 4, 2026
Bug IDs: CSCwq23369 , CSCwq23372 , CSCwq23373 , CSCwq23377 , CSCwq97494 , CSCwq97497 , CSCwq97658 , CSCwq97660 , CSCwq97748 , CSCwq97750 , CSCwr21406
The vendor’s rating applies to the whole advisory and can differ from this CVE’s own CVSS severity. Where this comes from