CVE-2025-20217

High

Description

A vulnerability in the packet inspection functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to incorrect processing of traffic that is inspected by an affected device. An attacker could exploit this vulnerability by sending crafted traffic through the affected device. A successful exploit could allow the attacker to cause the affected device to enter an infinite loop while inspecting traffic, resulting in a DoS condition. The system watchdog will restart the Snort process automatically.

SeverityHigh
CVSS8.6
Exploit probability—
ProductCisco Firepower Threat Defense Software
PublishedAug 14, 2025
First seenAug 14, 2025
Weakness typeCWE-835CWE-835

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Cisco Cisco Firepower Threat Defense Software7.1.0, 7.1.0.1, 7.2.0, 7.1.0.2, 7.2.0.1, 7.2.1, 7.3.0, 7.2.2, 7.2.3, 7.3.1, 7.1.0.3, 7.2.4, 7.2.5, 7.2.4.1, 7.3.1.1, 7.4.0, 7.2.5.1, 7.4.1, 7.2.6, 7.4.1.1, 7.2.7, 7.2.5.2, 7.3.1.2, 7.2.8, 7.6.0, 7.4.2, 7.2.8.1, 7.4.2.1, 7.2.9—

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.