--- id: CVE-2026-20007 title: >- 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 … summary: >- 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 … severity: medium cvss: 5.8 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N' cwe: - CWE-284 vendor: cisco product: secure_firewall_threat_defense affected: - secure_firewall_threat_defense = 6.4.0 - secure_firewall_threat_defense = 6.4.0.1 - secure_firewall_threat_defense = 6.4.0.2 - secure_firewall_threat_defense = 6.4.0.3 - secure_firewall_threat_defense = 6.4.0.4 - secure_firewall_threat_defense = 6.4.0.5 - secure_firewall_threat_defense = 6.4.0.6 - secure_firewall_threat_defense = 6.4.0.7 - secure_firewall_threat_defense = 6.4.0.8 - secure_firewall_threat_defense = 6.4.0.9 - secure_firewall_threat_defense = 6.4.0.10 - secure_firewall_threat_defense = 6.4.0.11 - secure_firewall_threat_defense = 6.4.0.12 - secure_firewall_threat_defense = 6.4.0.13 - secure_firewall_threat_defense = 6.4.0.14 - secure_firewall_threat_defense = 6.4.0.15 - secure_firewall_threat_defense = 6.4.0.16 - secure_firewall_threat_defense = 6.4.0.17 - secure_firewall_threat_defense = 6.4.0.18 - secure_firewall_threat_defense = 7.0.0 - secure_firewall_threat_defense = 7.0.0.1 - secure_firewall_threat_defense = 7.0.1 - secure_firewall_threat_defense = 7.0.1.1 - secure_firewall_threat_defense = 7.0.2 - secure_firewall_threat_defense = 7.0.2.1 - secure_firewall_threat_defense = 7.0.3 - secure_firewall_threat_defense = 7.0.4 - secure_firewall_threat_defense = 7.0.5 - secure_firewall_threat_defense = 7.0.6 - secure_firewall_threat_defense = 7.0.6.1 - secure_firewall_threat_defense = 7.0.6.2 - secure_firewall_threat_defense = 7.0.6.3 - secure_firewall_threat_defense = 7.0.7 - secure_firewall_threat_defense = 7.0.8 - secure_firewall_threat_defense = 7.0.8.1 - secure_firewall_threat_defense = 7.1.0 - secure_firewall_threat_defense = 7.1.0.1 - secure_firewall_threat_defense = 7.1.0.2 - secure_firewall_threat_defense = 7.1.0.3 - secure_firewall_threat_defense = 7.2.0 - secure_firewall_threat_defense = 7.2.0.1 - secure_firewall_threat_defense = 7.2.1 - secure_firewall_threat_defense = 7.2.2 - secure_firewall_threat_defense = 7.2.3 - secure_firewall_threat_defense = 7.2.4 - secure_firewall_threat_defense = 7.2.4.1 - secure_firewall_threat_defense = 7.2.5 - secure_firewall_threat_defense = 7.2.5.1 - secure_firewall_threat_defense = 7.2.5.2 - secure_firewall_threat_defense = 7.2.6 - secure_firewall_threat_defense = 7.2.7 - secure_firewall_threat_defense = 7.2.8 - secure_firewall_threat_defense = 7.2.8.1 - secure_firewall_threat_defense = 7.2.9 - secure_firewall_threat_defense = 7.2.10 - secure_firewall_threat_defense = 7.2.10.2 - secure_firewall_threat_defense = 7.3.0 - secure_firewall_threat_defense = 7.3.1 - secure_firewall_threat_defense = 7.3.1.1 - secure_firewall_threat_defense = 7.3.1.2 - secure_firewall_threat_defense = 7.4.0 - secure_firewall_threat_defense = 7.4.1 - secure_firewall_threat_defense = 7.4.1.1 - secure_firewall_threat_defense = 7.4.2 - secure_firewall_threat_defense = 7.4.2.1 - secure_firewall_threat_defense = 7.4.2.2 - secure_firewall_threat_defense = 7.4.2.3 - secure_firewall_threat_defense = 7.4.2.4 - secure_firewall_threat_defense = 7.6.0 - secure_firewall_threat_defense = 7.6.1 - secure_firewall_threat_defense = 7.6.2 - secure_firewall_threat_defense = 7.6.2.1 - secure_firewall_threat_defense = 7.7.0 published: '2026-03-04' updated: '2026-08-20' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20007' references: - url: >- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort-bypass-rLggKzVF label: psirt@cisco.com tags: - nvd epss: 0.00232 epssPercentile: 0.14323 ingestedAt: '2026-08-20T17:59:04.039Z' --- ## Overview 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. ## Affected - `secure_firewall_threat_defense = 6.4.0` - `secure_firewall_threat_defense = 6.4.0.1` - `secure_firewall_threat_defense = 6.4.0.2` - `secure_firewall_threat_defense = 6.4.0.3` - `secure_firewall_threat_defense = 6.4.0.4` - `secure_firewall_threat_defense = 6.4.0.5` - `secure_firewall_threat_defense = 6.4.0.6` - `secure_firewall_threat_defense = 6.4.0.7` - `secure_firewall_threat_defense = 6.4.0.8` - `secure_firewall_threat_defense = 6.4.0.9` - `secure_firewall_threat_defense = 6.4.0.10` - `secure_firewall_threat_defense = 6.4.0.11` - `secure_firewall_threat_defense = 6.4.0.12` - `secure_firewall_threat_defense = 6.4.0.13` - `secure_firewall_threat_defense = 6.4.0.14` - `secure_firewall_threat_defense = 6.4.0.15` - `secure_firewall_threat_defense = 6.4.0.16` - `secure_firewall_threat_defense = 6.4.0.17` - `secure_firewall_threat_defense = 6.4.0.18` - `secure_firewall_threat_defense = 7.0.0` - `secure_firewall_threat_defense = 7.0.0.1` - `secure_firewall_threat_defense = 7.0.1` - `secure_firewall_threat_defense = 7.0.1.1` - `secure_firewall_threat_defense = 7.0.2` - `secure_firewall_threat_defense = 7.0.2.1` - `secure_firewall_threat_defense = 7.0.3` - `secure_firewall_threat_defense = 7.0.4` - `secure_firewall_threat_defense = 7.0.5` - `secure_firewall_threat_defense = 7.0.6` - `secure_firewall_threat_defense = 7.0.6.1` - `secure_firewall_threat_defense = 7.0.6.2` - `secure_firewall_threat_defense = 7.0.6.3` - `secure_firewall_threat_defense = 7.0.7` - `secure_firewall_threat_defense = 7.0.8` - `secure_firewall_threat_defense = 7.0.8.1` - `secure_firewall_threat_defense = 7.1.0` - `secure_firewall_threat_defense = 7.1.0.1` - `secure_firewall_threat_defense = 7.1.0.2` - `secure_firewall_threat_defense = 7.1.0.3` - `secure_firewall_threat_defense = 7.2.0` - `secure_firewall_threat_defense = 7.2.0.1` - `secure_firewall_threat_defense = 7.2.1` - `secure_firewall_threat_defense = 7.2.2` - `secure_firewall_threat_defense = 7.2.3` - `secure_firewall_threat_defense = 7.2.4` - `secure_firewall_threat_defense = 7.2.4.1` - `secure_firewall_threat_defense = 7.2.5` - `secure_firewall_threat_defense = 7.2.5.1` - `secure_firewall_threat_defense = 7.2.5.2` - `secure_firewall_threat_defense = 7.2.6` - `secure_firewall_threat_defense = 7.2.7` - `secure_firewall_threat_defense = 7.2.8` - `secure_firewall_threat_defense = 7.2.8.1` - `secure_firewall_threat_defense = 7.2.9` - `secure_firewall_threat_defense = 7.2.10` - `secure_firewall_threat_defense = 7.2.10.2` - `secure_firewall_threat_defense = 7.3.0` - `secure_firewall_threat_defense = 7.3.1` - `secure_firewall_threat_defense = 7.3.1.1` - `secure_firewall_threat_defense = 7.3.1.2` - `secure_firewall_threat_defense = 7.4.0` - `secure_firewall_threat_defense = 7.4.1` - `secure_firewall_threat_defense = 7.4.1.1` - `secure_firewall_threat_defense = 7.4.2` - `secure_firewall_threat_defense = 7.4.2.1` - `secure_firewall_threat_defense = 7.4.2.2` - `secure_firewall_threat_defense = 7.4.2.3` - `secure_firewall_threat_defense = 7.4.2.4` - `secure_firewall_threat_defense = 7.6.0` - `secure_firewall_threat_defense = 7.6.1` - `secure_firewall_threat_defense = 7.6.2` - `secure_firewall_threat_defense = 7.6.2.1` - `secure_firewall_threat_defense = 7.7.0` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.