Cisco Secure Firewall Threat Defense Software TLS 1.3 DoS (cisco-sa-ftd-tls1-3-dos-dLxwFWgF)

high Nessus Plugin ID 348174

Synopsis

The remote device is missing a vendor-supplied security patch.

Description

According to its self-reported version, Cisco Secure Firewall Threat Defense (FTD) Software is affected by a denial of service vulnerability. A flaw exists within the TLS 1.3 implementation due to improper buffer management. An unauthenticated, remote attacker can exploit this issue, via a crafted TLS 1.3 packet, to cause the system to stop responding.

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

Solution

Upgrade to the relevant fixed version referenced in Cisco bug ID CSCwo83926

Plugin Details

Severity: High

ID: 348174

File Name: cisco-sa-ftd-tls1.3-dos-dLxwFWgF.nasl

Version: 1.1

Type: Combined

Family: CISCO

Published: 9/18/2026

Updated: 9/18/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.3

Percentile: 50.57

CVSS v2

Risk Factor: High

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-20135

CVSS v3

Risk Factor: High

Base Score: 8.6

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Vulnerability Information

CPE: cpe:/o:cisco:firepower_threat_defense

Required KB Items: installed_sw/Cisco Firepower Threat Defense

Patch Publication Date: 9/16/2026

Vulnerability Publication Date: 9/16/2026

Reference Information

CVE: CVE-2026-20135

CWE: 415

CISCO-SA: cisco-sa-ftd-tls1-3-dos-dLxwFWgF

IAVA: 2026-A-1027

CISCO-BUG-ID: CSCwo83926

Detections

Analytics