# CVE-2024-20481: Cisco ASA and FTD Denial-of-Service

> Unauthenticated remote attackers can cause a denial of service in Cisco ASA and FTD VPN services by exhausting resources through excessive authentication requests.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L`)
- **Exploited in the wild:** Yes, since 24 Oct 2024 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Oct 2024
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-cp3f-3wc5-j85w

## What is CVE-2024-20481?

CVE-2024-20481 is a medium-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, 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 Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service.

 This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authentication requests to an affected device. A successful exploit could allow the attacker to exhaust resources, resulting in a DoS of the RAVPN service on the affected device. Depending on the impact of the attack, a reload of the device may be required to restore the RAVPN service. Services that are not related to VPN are not affected.

 Cisco Talos discussed these attacks in the blog post Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials.

Weakness: CWE-772 (Missing Release of Resource after Effective Lifetime)

## Which versions are affected by CVE-2024-20481?

It affects 2 products.


Products: Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.

## How do I fix CVE-2024-20481?

No fix has been published for CVE-2024-20481 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 14 Nov 2024.

## Is CVE-2024-20481 being exploited?

Yes. Attackers have exploited CVE-2024-20481 in the wild since at least 24 Oct 2024.

## Other vulnerabilities in Cisco Adaptive Security Appliance Software

- [CVE-2025-20333](https://insights.sbomify.com/CVE-2025-20333/): Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow (critical 9.9, exploited in the wild)
- [CVE-2016-6366](https://insights.sbomify.com/CVE-2016-6366/): Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2026-20349](https://insights.sbomify.com/CVE-2026-20349/): Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection (high 8.6, exploited in the wild)
- [CVE-2024-20353](https://insights.sbomify.com/CVE-2024-20353/): Cisco ASA and FTD Denial of Service (high 8.6, exploited in the wild)
- [CVE-2016-6367](https://insights.sbomify.com/CVE-2016-6367/): Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-20481 and fix it if it is affected.

What it is: CVE-2024-20481 is a medium-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 23 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2024-20481 in the wild since at least 24 Oct 2024.

Affected product: Cisco Adaptive Security Appliance 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-2024-20481/ (Markdown: https://insights.sbomify.com/CVE-2024-20481/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-20481
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-20481
- OSV: https://osv.dev/vulnerability/CVE-2024-20481

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-20481/
Summaries are generated and may contain mistakes; the official description above is the record.