# CVE-2024-20339: Cisco Firepower Threat Defense Software for Firepower 2100 Series TLS Denial of Service Vulnerability

> Unauthenticated remote attackers can cause a denial of service by sending specific TLS traffic, crashing Cisco Firepower 2100 devices.

- **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:** 23 Oct 2024
- **Updated:** 24 Oct 2024
- **Also known as:** GHSA-7874-r67m-25qh

## What is CVE-2024-20339?

CVE-2024-20339 is a high-severity vulnerability in Cisco Secure Firewall Threat Defense, published on 23 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to an issue that occurs when TLS traffic is processed. An attacker could exploit this vulnerability by sending certain TLS traffic over IPv4 through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition and impacting traffic to and through the affected device.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-20339?

It affects 1 product.


Products: Cisco Secure Firewall Threat Defense.

## How do I fix CVE-2024-20339?

No fix has been published for CVE-2024-20339 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-20339 being exploited?

There is no known exploitation of CVE-2024-20339 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Secure Firewall Threat Defense

- [CVE-2024-20412](https://insights.sbomify.com/CVE-2024-20412/): Hardcoded credentials in Cisco Firepower Threat Defense Software (critical 9.3)
- [CVE-2024-20330](https://insights.sbomify.com/CVE-2024-20330/): Memory corruption in Cisco Firepower Threat Defense Software (high 8.6)
- [CVE-2024-20351](https://insights.sbomify.com/CVE-2024-20351/): Cisco Firepower Threat Defense Software Snort Firewall Denial of Service Vulnerability (high 8.6)
- [CVE-2023-20083](https://insights.sbomify.com/CVE-2023-20083/): Denial of service in Cisco Firepower Threat Defense Software (high 8.6)
- [CVE-2023-20244](https://insights.sbomify.com/CVE-2023-20244/): Denial of service in Cisco Firepower Threat Defense Software (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-20339 and fix it if it is affected.

What it is: CVE-2024-20339 is a high-severity vulnerability in Cisco Secure Firewall Threat Defense, published on 23 Oct 2024. 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-2024-20339 in the wild and no public exploit code.

Affected product: Cisco Secure Firewall Threat Defense. 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-2024-20339/ (Markdown: https://insights.sbomify.com/CVE-2024-20339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-20339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-20339
- OSV: https://osv.dev/vulnerability/CVE-2024-20339

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-20339/
Summaries are generated and may contain mistakes; the official description above is the record.