CVE-2026-20007

Cisco Secure Firewall Threat Defense Software Snort Deep Inspection Bypass Vulnerability

Severity
Medium 5.8
CVSS 3.1
Exploited
Not listed
EPSS
0.002
16.0th percentile
Discovered by
Third party
Published by the vendor
Published
Mar 4, 2026
Assigned by cisco

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.

Weakness: CWE-284

Affected products

Vendor Product Category Matched by
Cisco Cisco Secure Firewall Firewall / NGFW cna-assigner
Vendor-reported affected versions (1)
  • Cisco · Cisco Secure Firewall Threat Defense (FTD) Software