CVE-2025-20217 Cisco Firepower Threat Defense Intrusion Detection Denial of Service Vulnerability
Remote attackers can cause a denial of service on Cisco Firepower Threat Defense devices by sending crafted traffic that triggers an infinite loop in the Snort engine.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20217?
CVE-2025-20217 is a high-severity denial of service vulnerability in Cisco Firepower Threat Defense Software, published on 14 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-835
Which versions are affected by CVE-2025-20217?
How do I fix CVE-2025-20217?
No fix has been published for CVE-2025-20217 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-20217 being exploited?
There is no known exploitation of CVE-2025-20217 in the wild and no public exploit code.
Sources
Also known as GHSA-w2gg-j3hp-gfqv.