CVE-2026-20058: Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Denial of Service Vulnerability

Published Mar 4, 2026
·
Updated

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 Software

70 affected components
Cisco Secure Firewall Threat Defense Software
Cisco Snort 3
Cisco Snort>=3.0.0-233<3.9.6.0
Cisco Secure Firewall Threat Defense=7.2.0
Cisco Secure Firewall Threat Defense=7.2.0.1
Cisco Secure Firewall Threat Defense=7.2.1
Cisco Secure Firewall Threat Defense=7.2.2
Cisco Secure Firewall Threat Defense=7.2.3
Cisco Secure Firewall Threat Defense=7.2.4
Cisco Secure Firewall Threat Defense=7.2.4.1
Cisco Secure Firewall Threat Defense=7.2.5
Cisco Secure Firewall Threat Defense=7.2.5.1
Cisco Secure Firewall Threat Defense=7.2.5.2
Cisco Secure Firewall Threat Defense=7.2.6
Cisco Secure Firewall Threat Defense=7.2.7
Cisco Secure Firewall Threat Defense=7.2.8
Cisco Secure Firewall Threat Defense=7.2.8.1
Cisco Secure Firewall Threat Defense=7.2.9
Cisco Secure Firewall Threat Defense=7.2.10
Cisco Secure Firewall Threat Defense=7.2.10.2
Cisco Secure Firewall Threat Defense=7.3.0
Cisco Secure Firewall Threat Defense=7.3.1
Cisco Secure Firewall Threat Defense=7.3.1.1
Cisco Secure Firewall Threat Defense=7.3.1.2
Cisco Secure Firewall Threat Defense=7.4.0
Cisco Secure Firewall Threat Defense=7.4.1
Cisco Secure Firewall Threat Defense=7.4.1.1
Cisco Secure Firewall Threat Defense=7.4.2
Cisco Secure Firewall Threat Defense=7.4.2.1
Cisco Secure Firewall Threat Defense=7.4.2.2
Cisco Secure Firewall Threat Defense=7.4.2.3
Cisco Secure Firewall Threat Defense=7.4.2.4
Cisco Secure Firewall Threat Defense=7.4.3
Cisco Secure Firewall Threat Defense=7.6.0
Cisco Secure Firewall Threat Defense=7.6.1
Cisco Secure Firewall Threat Defense=7.6.2
Cisco Secure Firewall Threat Defense=7.6.2.1
Cisco Secure Firewall Threat Defense=7.7.0
Cisco Secure Firewall Threat Defense=7.7.10
Cisco Secure Firewall Threat Defense=7.7.10.1
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.3a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.5a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.3a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.4a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.4b
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.5a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.5b
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.5c
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.5d
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.12.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.13.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.14.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.2a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.2c
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.3a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.15.4c
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.16.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.17.1
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.18.1
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.18.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.18.2

Event History

Mar 4, 2026
CVE Published
via MITRE·05:47 PM
Data Sourced
via MITRE·05:47 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:16 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-20058?

The severity of CVE-2026-20058 is rated as critical due to the potential for unauthenticated remote attackers to crash the Snort 3 Detection Engine.

2

How do I fix CVE-2026-20058?

To fix CVE-2026-20058, ensure that your Cisco Secure Firewall Threat Defense Software or Cisco Snort 3 is updated to the latest version that addresses this vulnerability.

3

Who is affected by CVE-2026-20058?

CVE-2026-20058 affects users of Cisco Secure Firewall Threat Defense Software and Cisco Snort 3 utilizing the Snort 3 Visual Basic for Application feature.

4

What are the potential impacts of CVE-2026-20058?

The potential impacts of CVE-2026-20058 include denial of service, leading to disruption in threat detection and response capabilities.

5

Is CVE-2026-20058 a remote vulnerability?

Yes, CVE-2026-20058 is a remote vulnerability that can be exploited by attackers without authentication.

Company

Resources

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