Secure Firewall Threat Defense
CVE-2026-20007
MEDIUM
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Primary rating from Vendor (cisco) · only source for this CVE.
CVSS VectorVendor: cisco
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Snort rule bypass in Cisco Secure Firewall Threat Defense allows unauthenticated remote attackers to evade deep packet inspection through crafted traffic that exploits logic errors in inner and outer connection rule evaluation. An attacker can send specially crafted packets that trigger different Snort rules than intended, permitting malicious traffic through the firewall that should be blocked. No patch is currently available for this medium-severity vulnerability.
Technical ContextAI
Classified as CWE-284 (Improper Access Control). 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
RemediationAI
Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.
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Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
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External POC / Exploit Code
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