CVE-2026-20067: Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability

Published Mar 4, 2026
·
Updated

Multiple Cisco products are affected by a vulnerability in the Snort 3 detection engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.  This vulnerability is due to incomplete error checking when parsing the Multicast DNS fields of the HTTP header. An attacker could exploit this vulnerability by sending crafted HTTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine unexpectedly restarts.

Affected Software

183 affected components
Cisco Snort 3
Cisco Snort>=3.0.0-233<3.9.5.0
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=7.0.0
Cisco Secure Firewall Threat Defense=7.0.0.1
Cisco Secure Firewall Threat Defense=7.0.1
Cisco Secure Firewall Threat Defense=7.0.1.1
Cisco Secure Firewall Threat Defense=7.0.2
Cisco Secure Firewall Threat Defense=7.0.2.1
Cisco Secure Firewall Threat Defense=7.0.3
Cisco Secure Firewall Threat Defense=7.0.4
Cisco Secure Firewall Threat Defense=7.0.5
Cisco Secure Firewall Threat Defense=7.0.6
Cisco Secure Firewall Threat Defense=7.0.6.1
Cisco Secure Firewall Threat Defense=7.0.6.2
Cisco Secure Firewall Threat Defense=7.0.6.3
Cisco Secure Firewall Threat Defense=7.0.7
Cisco Secure Firewall Threat Defense=7.0.8
Cisco Secure Firewall Threat Defense=7.0.8.1
Cisco Secure Firewall Threat Defense=7.1.0
Cisco Secure Firewall Threat Defense=7.1.0.1
Cisco Secure Firewall Threat Defense=7.1.0.2
Cisco Secure Firewall Threat Defense=7.1.0.3
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=17.2.1r
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

Event History

Mar 4, 2026
CVE Published
via MITRE·05:49 PM
Data Sourced
via MITRE·05:49 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:16 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-20067?

CVE-2026-20067 is classified as a critical severity vulnerability due to its potential impact on system availability.

2

How do I fix CVE-2026-20067?

To fix CVE-2026-20067, ensure you are using the latest version of the Cisco Snort 3 detection engine with the recommended security patches.

3

What potential impact does CVE-2026-20067 have on my Cisco products?

CVE-2026-20067 may allow an unauthenticated remote attacker to cause the Snort 3 Detection Engine to restart, impacting network traffic processing.

4

Is CVE-2026-20067 exploitable remotely?

Yes, CVE-2026-20067 can be exploited by an unauthenticated remote attacker.

5

Which products are affected by CVE-2026-20067?

CVE-2026-20067 affects multiple Cisco products that utilize the Snort 3 detection engine.

Company

Resources

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