CVE-2024-20353
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.
Key facts
- CVSS score
- 8.6 (v3.1)
- Severity
- HIGH
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- Weakness (CWE)
- CWE-835
- EPSS score
- 70.7% (99th percentile)
- In CISA KEV
- Yes, added April 24, 2024
- In EU EUVD
- Yes (EUVD-2024-18068)
- Published
- April 24, 2024
- NVD last modified
- August 11, 2026
- Status
- Analyzed
CISA Known Exploited Vulnerability
Cisco ASA and FTD Denial of Service Vulnerability
Added to the KEV catalog on April 24, 2024; federal remediation due May 1, 2024.
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2024-18068 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on October 21, 2025.
View on the EU Vulnerability DatabaseAffected products
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
- cisco / adaptive security appliance software
and 217 more…
Certified products that may be affected
2 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- Cisco Secure Firewall Threat Defense (FTD) 7.4 with Secure Firewall Management Center (FMC) 7.4 and Secure Client 5.1 - Cisco Systems, Inc. - Common Criteria NSCIB-CC-2400046-01-CR - active
- Cisco Secure Firewall Threat Defense Virtual 7.4 with FMC/FMCv - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-11510-2025 - active
References
- https://blog.talosintelligence.com/arcanedoor-new-espionage-focused-campaign-found-targeting-perimeter-network-devices/(Exploit, Third Party Advisory)
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2(Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20353(US Government Resource)
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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