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Medium · 5.8 CVE-2026-20218 EUVD-2026-107375GHSA-vvhg-cxrm-qp98

Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability

Published Oct 21, 2026 · Updated Oct 22, 2026 · Assigned by cisco

Description

A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco products could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.  

This vulnerability is due to improper range checking when Snort 3 decompresses VBA data, which is user controlled. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine of a targeted device. A successful exploit could allow the attacker to cause an overflow of stack data, which could result in a DoS condition.

Affected products

VendorProductAffectedFixed
Cisco Cisco Open Source Snort3 3.12.2.0, 3.1.2.0, 3.1.3.0, 3.1.4.0, 3.1.5.0, 3.1.6.0, 3.1.7.0, 3.1.8.0, 3.1.9.0, 3.1.10.0, 3.1.12.0, 3.1.13.0, 3.1.14.0, 3.1.15.0, 3.1.16.0, 3.1.17.0, 3.1.18.0, 3.1.19.0, 3.1.20.0, 3.1.21.0, 3.1.22.0, 3.1.23.0, 3.1.24.0, 3.1.25.0, 3.1.27.0, 3.1.28.0, 3.1.29.0, 3.1.30.0, 3.1.31.0, 3.1.32.0, 3.1.36.… —
Cisco Cisco Secure Firewall Threat Defense (FTD) Software 7.2.0, 7.2.0.1, 7.2.1, 7.3.0, 7.2.2, 7.2.3, 7.3.1, 7.2.4, 7.2.5, 7.2.4.1, 7.3.1.1, 7.4.0, 7.2.5.1, 7.4.1, 7.2.6, 7.4.1.1, 7.2.7, 7.2.5.2, 7.3.1.2, 7.2.8, 7.6.0, 7.4.2, 7.2.8.1, 7.4.2.1, 7.2.9, 7.7.0, 7.4.2.2, 7.2.10, 7.6.1, 7.4.2.3, 7.6.2, 7.7.10, 7.7.11, 7.6.2.1, 7.7.10.1, 7.4.2.4, 7.2.10.2, 7.4.3… —
Cisco Cisco UTD SNORT IPS Engine Software 17.12.1a, 17.12.2, 17.13.1a, 17.12.3, 17.14.1a, 17.12.4, 17.12.3a, 17.15.1a, 17.16.1a, 17.12.4a, 17.15.2c, 17.12.4b, 17.15.2a, 17.12.5, 17.17.1, 17.12.5a, 17.15.3a, 17.15.3, 17.12.5b, 17.12.5c, 17.15.4, 17.18.1, 17.18.1a, 17.12.6, 17.15.4c, 17.12.5d, 17.18.2, 26.1.1, 17.15.5, 17.15.5a, 17.12.7, 17.… —

Advisories 2

References