# CVE-2024-20353: Cisco ASA and FTD Denial of Service Vulnerability

> CVE-2024-20353: Cisco ASA and FTD Denial of Service Vulnerability. CVSS 8.6 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2024-20353
Last updated: 2025-10-21T23:05:20Z

- Published: 2024-04-24 18:15 UTC · Updated: 2025-10-21 23:05 UTC · Assigner: cisco
- CVSS: 8.6 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- EPSS: 69.8%, 99th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2024-04-24, federal due date 2024-05-01, ransomware use: Unknown
- CWE: CWE-835

## Description

A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. 
 This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.

## CISA required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

## Affected vendors and products

- cisco: asa
- cisco: firepower\_threat\_defense\_software
- Cisco: Cisco Adaptive Security Appliance (ASA) Software
- Cisco: Cisco Firepower Threat Defense Software

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2024-20353)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2024-20353)
- [https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2024-20353 · Markdown: https://rewindex.com/cve/CVE-2024-20353.md · JSON: https://rewindex.com/api/v1/cves/CVE-2024-20353 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:12:43.501Z