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)…
Browse: All 2024 CVEs · All vendors
- CVSS score
- 8.6 High
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- CISA KEV
- Yes — actively exploited (added 2024-04-24, remediation due 2024-05-01)
- Weakness (CWE)
- CWE-835
- Published
- 2024-04-24
- Last modified
- 2026-08-11
- NVD status
- Analyzed
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.
Affected products
- cisco adaptive security appliance software
- cisco secure firewall threat defense
Affected ranges per NVD CPE data; confirm exact versions in the vendor advisory.
Required action (CISA)
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Federal remediation deadline: 2024-05-01.
How to prioritize this
This vulnerability is on the CISA KEV list, meaning it is being actively exploited — treat it as urgent regardless of the raw CVSS number. Use the live CVE lookup for the latest NVD data, and the CVSS 3.1 calculator to model your own environmental score.
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
FAQ
Is CVE-2024-20353 actively exploited?
Yes. CISA added CVE-2024-20353 to its Known Exploited Vulnerabilities (KEV) catalog on 2024-04-24, with a federal remediation deadline of 2024-05-01. A KEV listing means real-world exploitation is confirmed, so patching this should be prioritized above many higher-CVSS bugs that aren't being exploited.
What is the CVSS score of CVE-2024-20353?
CVE-2024-20353 has a CVSS base score of 8.6 (High). Its vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
Related vulnerabilities
- CVE-2024-20481 — Cisco Adaptive Security Appliance (ASA) an
- CVE-2024-20359 — Cisco Adaptive Security Appliance (ASA) an
- CVE-2020-3259 — Cisco Adaptive Security Appliance (ASA) an
- CVE-2020-3452 — Cisco Adaptive Security Appliance (ASA) an
- CVE-2020-3580 — Cisco Adaptive Security Appliance (ASA) an
- CVE-2026-20349 — Cisco Secure Firewall Adaptive Security Ap
Data source: NVD & CISA KEV. Shown as-is; nothing added. Last generated from NVD data — re-check the live tool for updates.
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