# 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.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Aug 2025
- **Updated:** 14 Aug 2025
- **Also known as:** GHSA-w2gg-j3hp-gfqv

## 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 (Loop with Unreachable Exit Condition)

## 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.

## Is CVE-2025-20217 being exploited?

There is no known exploitation of CVE-2025-20217 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-20217 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-20217 in the wild and no public exploit code.

Affected product: Cisco Firepower Threat Defense Software. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-20217/ (Markdown: https://insights.sbomify.com/CVE-2025-20217/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-20217
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-20217
- OSV: https://osv.dev/vulnerability/CVE-2025-20217

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-20217/
Summaries are generated and may contain mistakes; the official description above is the record.