CVE-2026-20054: Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Infinite Loop Denial of Service Vulnerability

Published Mar 4, 2026
·
Updated

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 error checking when decompressing VBA data. 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 the Snort 3 Detection Engine to enter an infinite loop, causing a DoS condition.

Affected Software

195 affected components
Cisco Secure Firewall Threat Defense Software
Cisco Snort>=3.0.0-233<3.9.3.0
Cisco Cyber Vision=3.0.0
Cisco Cyber Vision=3.0.1
Cisco Cyber Vision=3.0.2
Cisco Cyber Vision=3.0.3
Cisco Cyber Vision=3.0.4
Cisco Cyber Vision=3.0.5
Cisco Cyber Vision=3.0.6
Cisco Cyber Vision=3.1.0
Cisco Cyber Vision=3.1.1
Cisco Cyber Vision=3.1.2
Cisco Cyber Vision=3.2.0
Cisco Cyber Vision=3.2.1
Cisco Cyber Vision=3.2.2
Cisco Cyber Vision=3.2.3
Cisco Cyber Vision=3.2.4
Cisco Cyber Vision=4.0.0
Cisco Cyber Vision=4.0.1
Cisco Cyber Vision=4.0.2
Cisco Cyber Vision=4.0.3
Cisco Cyber Vision=4.1.0
Cisco Cyber Vision=4.1.1
Cisco Cyber Vision=4.1.2
Cisco Cyber Vision=4.1.3
Cisco Cyber Vision=4.1.4
Cisco Cyber Vision=4.1.5
Cisco Cyber Vision=4.1.6
Cisco Cyber Vision=4.1.7
Cisco Cyber Vision=4.2.0
Cisco Cyber Vision=4.2.1
Cisco Cyber Vision=4.2.2
Cisco Cyber Vision=4.2.3
Cisco Cyber Vision=4.2.4
Cisco Cyber Vision=4.2.6
Cisco Cyber Vision=4.3.0
Cisco Cyber Vision=4.3.1
Cisco Cyber Vision=4.3.2
Cisco Cyber Vision=4.3.3
Cisco Cyber Vision=4.4.0
Cisco Cyber Vision=4.4.1
Cisco Cyber Vision=4.4.2
Cisco Cyber Vision=4.4.3
Cisco Cyber Vision=5.0.0
Cisco Cyber Vision=5.0.1
Cisco Cyber Vision=5.0.2
Cisco Cyber Vision=5.1.0
Cisco Cyber Vision=5.1.1
Cisco Cyber Vision=5.1.2
Cisco Cyber Vision=5.1.3
Cisco Cyber Vision=5.2.0
Cisco Cyber Vision=5.2.1
Cisco Cyber Vision=5.3.0
Cisco Cyber Vision=5.3.1
Cisco Cyber Vision=5.3.2
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=3.17.0s
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=3.17.1s
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.6.1
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.6.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.6.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.6.7a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.6.9
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.6.10
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.7
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=16.12.8
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.1.1
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.2.1r
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.4a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.7
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.8
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.3.8a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.4.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.4.1b
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.4.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.5.1
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.5.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.3a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.6a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.7
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.8
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.6.8a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.7.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.7.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.8.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.2a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.3a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.4a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.5a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.5e
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.5f
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.7a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.7b
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.8
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.10.1a
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.11.1a
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
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=denali-16.3.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=denali-16.3.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=denali-16.3.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=denali-16.3.7
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=denali-16.3.9
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=everest-16.6.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=everest-16.6.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=everest-16.6.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.2
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.3
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.5
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.6
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.7
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=fuji-16.9.8

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-2026-20054?

CVE-2026-20054 has a severity rating that classifies it as a denial of service vulnerability.

2

How do I fix CVE-2026-20054?

To fix CVE-2026-20054, you should apply the latest patches provided by Cisco for the affected Snort 3 VBA feature.

3

What products are affected by CVE-2026-20054?

CVE-2026-20054 affects multiple Cisco products that utilize Cisco Secure Firewall Threat Defense Software.

4

Who can exploit CVE-2026-20054?

CVE-2026-20054 can be exploited by unauthenticated remote attackers, leading to a denial of service.

5

What is the impact of CVE-2026-20054?

The impact of CVE-2026-20054 includes potential disruption of the Snort 3 Detection Engine, leading to service unavailability.

Company

Resources

Contact

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