CVE DATABASE / CVE-2024-20353
CVE-2024-20353
Cisco ASA and FTD Denial of Service Vulnerability
Confirmed exploited in the wild. Added 2024-04-24.
Federal remediation due 2024-05-01.
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Summary
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.
CVSS 3.1 breakdown
| Base score | 8.6 (HIGH) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | CHANGED |
| Confidentiality | NONE |
| Integrity | NONE |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Use our free CVE Lookup tool for the latest NVD record, or browse the full CISA KEV catalog.
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2
- https://blog.talosintelligence.com/arcanedoor-new-espionage-focused-campaign-found-targeting-perimeter-network-devices/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20353
Data: NIST NVD + CISA KEV. NVD last modified 2025-10-28. Always verify against the vendor advisory before acting.