CVE-2026-20218: medium-severity vulnerability in Cisco Open Source Snort3
Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.8epss 0.6%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Affected products
Cisco · Cisco Open Source Snort3Cisco · Cisco Secure Firewall Threat Defense (FTD) SoftwareCisco · Cisco UTD SNORT IPS Engine SoftwareRelated CVEs — Cisco Open Source Snort3
In the same product, most dangerous first.
CVE-2025-20362MEDIUMCVE-2025-20362EPSS 86.7%KEVCVE-2025-20333CRITICALCVE-2025-20333EPSS 72.0%KEVCVE-2026-20349HIGHCisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service VulnerabilityEPSS 1.0%KEVCVE-2026-76418HIGHCisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Tunnel Denial of Service VulnerabilityEPSS 0.8%KEVCVE-2021-1285HIGHMultiple Cisco Products SNORT Ethernet Frame Decoder Denial of Service VulnerabilityEPSS 2.9%CVE-2022-20685HIGHMultiple Cisco Products Snort Modbus Denial of Service VulnerabilityEPSS 1.5%