CVE-2026-20058: Cisco Secure Firewall Threat Defense

Medium severity, CVSS 5.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Multiple Cisco products are affected by vulnerabilities in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. These vulnerabilities are due to improper error checking when decompressing VBA data. An attacker could exploit these vulnerabilities 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 unexpectedly restart, causing a DoS condition.

Affected products

• Cisco Secure Firewall Threat Defense: version 7.2.0 only; version 7.2.0.1 only; version 7.2.1 only; version 7.2.2 only; version 7.2.3 only; version 7.2.4 only; …
• Cisco Snort: from 3.0.0-233, before 3.9.6.0 (fixed in 3.9.6.0)
• Cisco Unified Threat Defense Snort Intrusion Prevention System Engine: version 17.9.3a only; version 17.9.5a only; version 17.9.6 only; version 17.12.1a only; version 17.12.2 only; version 17.12.3 only; …

Published 2026-03-04. Last modified 2026-08-20.