CVE-2026-20006

Cisco Firepower Threat Defense Software and Cisco FirePOWER Services TLS with Snort 3 Denial of Service Vulnerability

State: Published
Severity: 5.8 Medium
Published: Mar 4, 2026
Updated: Mar 4, 2026
Reserved: Oct 8, 2025

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.

Scores

CVSS	Score	Vector	Source
3.1	5.8 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L	cisco

Weaknesses

CWE-388 Error Handling

Affected Products

Product	Versions
Cisco Secure Firewall Threat Defense (FTD) SoftwareCisco	7.2.0Affected 7.2.0.1Affected 7.2.1Affected 7.3.0Affected 7.2.2Affected 7.2.3Affected 7.3.1Affected 7.2.4Affected 7.2.5Affected 7.2.4.1Affected 7.3.1.1Affected 7.4.0Affected 7.2.5.1Affected 7.4.1Affected 7.2.6Affected 7.4.1.1Affected 7.2.7Affected 7.2.5.2Affected 7.3.1.2Affected 7.2.8Affected 7.6.0Affected 7.4.2Affected 7.2.8.1Affected 7.4.2.1Affected 7.2.9Affected and 8 more versions

References

cisco-sa-ftd-tcp-dos-rHfqnwRg

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.