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Cisco Secure Firewall Threat Defense Software TLS 1.3 Denial of Service Vulnerability

CVSS 3.1 8.6 HIGHCheck source for fixed versionsKEV status unknown

cve-program · CVE-2026-20135

Published

A vulnerability in the TLS 1.3 implementation in Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper buffer management during the TLS 1.3 connection. An attacker could exploit this vulnerability by sending a crafted TLS 1.3 packet to an affected system through a TLS 1.3-enabled listening socket. A successful exploit could allow the attacker to cause the LINA process to crash, which would cause the device to reload. The reload can happen before or after authentication of the connection.Note: TLS 1.3 connections include both data traffic and user-management traffic.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-20135

Published

Cisco Secure Firewall Threat Defense (FTD) Software

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "Cisco",
                    "product": "Cisco Secure Firewall Threat Defense (FTD) Software",
                    "versions": [
                        {
                            "version": "7.0.0",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.0.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.1.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.0",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.2.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.3",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.0.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.4",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.5",
                            "status": "affected"
                        },
                        {
                            "version": "7.3.0",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.3",
                            "status": "affected"
                        },
                        {
                            "version": "7.3.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.4",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.6",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.5",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.4.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.3.1.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.0",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.6.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.5.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.6",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.6.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.1.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.7",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.5.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.3.1.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.8",
                            "status": "affected"
                        },
                        {
                            "version": "7.6.0",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.8.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.6.3",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.2.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.9",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.7",
                            "status": "affected"
                        },
                        {
                            "version": "7.7.0",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.2.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.10",
                            "status": "affected"
                        },
                        {
                            "version": "7.6.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.2.3",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.8",
                            "status": "affected"
                        },
                        {
                            "version": "7.6.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.7.10",
                            "status": "affected"
                        },
                        {
                            "version": "7.7.11",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.8.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.6.2.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.7.10.1",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.2.4",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.10.2",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.3",
                            "status": "affected"
                        },
                        {
                            "version": "7.6.4",
                            "status": "affected"
                        },
                        {
                            "version": "7.4.4",
                            "status": "affected"
                        },
                        {
                            "version": "7.0.9",
                            "status": "affected"
                        },
                        {
                            "version": "7.2.11",
                            "status": "affected"
                        }
                    ],
                    "defaultStatus": "unknown"
                }

Original source record · Cite this exact observation · Complete original publisher JSON

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