CVE-2024-20353 HIGH

CVE-2024-20353

Vendor Cisco
Product Cisco Adaptive Security Appliance (ASA) Software
Weakness CWE-835
KEV Status Known Exploited
Published April 24, 2024
Last update October 21, 2025

CVSS base score

8.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

What the vulnerability does

01Description

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 mandated remediation

02CISA Required Action

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

Key dates

03Disclosure timeline

April 24, 2024 CVE published
October 21, 2025 Record updated