cisco-sa-ftd-snort-bypass-rLggKzVFMediumCVSS 5.8

Cisco Secure Firewall Threat Defense Software Snort Deep Inspection Bypass Vulnerability

Published
March 4, 2026
Last Modified
March 4, 2026

🔗 CVE IDs covered (1)

CVE-2026-20007 →

📋 Description

A vulnerability in the Snort 2 and Snort 3 deep packet inspection of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured Snort rules and allow traffic onto the network that should have been dropped.

This vulnerability is due to a logic error in the integration of the Snort Engine rules with Cisco Secure FTD Software that could allow different Snort rules to be hit when deep inspection of the packet is performed for the inner and outer connections. An attacker could exploit this vulnerability by sending crafted traffic to a targeted device that would hit configured Snort rules. A successful exploit could allow the attacker to send traffic to a network where it should have been denied.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is part of the March 2026 release of the Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2026 Semiannual Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75736"].

CVE-2026-20007 — Cisco Secure Firewall Threat Defense Software Snort Deep Inspection Bypass Vulnerability (CVSS 3.1 5.8, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)

🎯 Affected products63

  • Cisco 3000 Series Industrial Security Appliances (ISA)
  • Cisco ASA 5500-X Series Firewalls
  • Cisco Firepower 1000 Series
  • Cisco Firepower 2100 Series
  • Cisco Firepower 4100 Series
  • Cisco Firepower 9000 Series
  • Cisco Secure Firewall 1200 Series
  • Cisco Secure Firewall 3100 Series
  • Cisco Secure Firewall 4200 Series
  • Cisco Secure Firewall Threat Defense (FTD) Software
  • Cisco Secure Firewall Threat Defense Virtual
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.0
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.0.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.1.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.2
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.2.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.3
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.4
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.5
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.2
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.3
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.7
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.8
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.0.8.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0.1
  • Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0.2
  • +33 more not shown

✅ Remediation

Cisco has released software updates that address this vulnerability. https://software.cisco.com Workarounds: There are no workarounds that address this vulnerability.

🔗 References (6)