CVE-2026-20053: Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Heap Overflow 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 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 Software

121 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=17.9.4
Cisco Unified Threat Defense Snort Intrusion Prevention System Engine=17.9.5e
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·05:46 PM
Data Sourced
via MITRE·05:46 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:16 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-20053?

CVE-2026-20053 is classified as a high-severity vulnerability due to its potential for causing a denial of service.

2

How do I fix CVE-2026-20053?

To mitigate CVE-2026-20053, update to the latest version of Cisco Secure Firewall Threat Defense Software that addresses this vulnerability.

3

What type of vulnerability is CVE-2026-20053?

CVE-2026-20053 is a heap overflow vulnerability in the Snort 3 Visual Basic for Applications feature.

4

Who is affected by CVE-2026-20053?

CVE-2026-20053 affects multiple products using Cisco Secure Firewall Threat Defense Software with Snort 3.

5

Can CVE-2026-20053 be exploited remotely?

Yes, CVE-2026-20053 can be exploited by unauthenticated remote attackers.

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