CVE-2026-20053: Cisco Cyber Vision

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

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.

Affected products

• Cisco Cyber Vision: version 3.0.0 only; version 3.0.1 only; version 3.0.2 only; version 3.0.3 only; version 3.0.4 only; version 3.0.5 only; …
• 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 3.9.3.0 (fixed in 3.9.3.0)
• Cisco Unified Threat Defense Snort Intrusion Prevention System Engine: version 17.9.4 only; version 17.9.5e only; version 17.12.1a only; version 17.12.2 only; version 17.12.3 only; version 17.12.3a only; …

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