A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition.

This vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition. 
Note: TLS 1.3 is not affected by this vulnerability.

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Solution

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Workaround

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History

Wed, 04 Mar 2026 17:45:00 +0000

Type Values Removed Values Added
Description A vulnerability in the TLS cryptography functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to unexpectedly restart, resulting in a denial of service (DoS) condition. This vulnerability is due to improper implementation of the TLS protocol. An attacker could exploit this vulnerability by sending a crafted TLS packet to an affected system. A successful exploit could allow the attacker to cause a device that is running Cisco Secure FTD Software to drop network traffic, resulting in a DoS condition.  Note: TLS 1.3 is not affected by this vulnerability.
Title Cisco Firepower Threat Defense Software and Cisco FirePOWER Services TLS with Snort 3 Denial of Service Vulnerability
Weaknesses CWE-388
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2026-03-04T20:51:58.937Z

Reserved: 2025-10-08T11:59:15.349Z

Link: CVE-2026-20006

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-04T18:16:13.803

Modified: 2026-03-04T18:16:13.803

Link: CVE-2026-20006

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses