---
title: "CVE-2024-20481: Cisco ASA and FTD Denial-of-Service Vulnerability"
url: https://erroneo.us/security/cve/CVE-2024-20481/
description: "CVE-2024-20481 (Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)): Exploited in the wild (CISA KEV). A vulnerability in the Remote…"
type: vulnerability-record
section: "Security Digest"
date_published: 2024-10-23
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2024-20481"
kev: true
cvss: 5.8
epss: 0.15874
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD). CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-10-24, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-11-14 ; treat that as the outer limit, not the target.
- EPSS 15.9% , percentile 97: FIRST’s model estimates a 15.9% chance of exploitation activity in the next 30 days, higher than 97% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

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.

## Affected products (CVE record)

- Cisco Cisco Adaptive Security Appliance (ASA) Software: 9.8.1, 9.8.1.5, 9.8.1.7, 9.8.2, 9.8.2.8, 9.8.2.14, 9.8.2.15, 9.8.2.17, 9.8.2.20, 9.8.2.24, 9.8.2.26, 9.8.2.28
- Cisco Cisco Firepower Threat Defense Software: 6.2.3, 6.2.3.1, 6.2.3.2, 6.2.3.3, 6.2.3.4, 6.2.3.5, 6.2.3.6, 6.2.3.7, 6.2.3.8, 6.2.3.10, 6.2.3.11, 6.2.3.9

## Severity

- cisco CVSS 3.1: 5.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L`

## Exploitation

- CISA KEV: added 2024-10-24; federal due date 2024-11-14. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 15.87% probability of exploitation activity in the next 30 days; percentile 97.

## Sources

- [Listed in CISA KEV notes (sec.cloudapps.cisco.com)](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-bf-dos-vDZhLqrW)
- [CVE.org record CVE-2024-20481](https://www.cve.org/CVERecord?id=CVE-2024-20481)
- [NVD entry CVE-2024-20481](https://nvd.nist.gov/vuln/detail/CVE-2024-20481)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20481)

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Source page: https://erroneo.us/security/cve/CVE-2024-20481/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt