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CVE-2024-20353

Cisco ASA and FTD Denial of Service Vulnerability

  • High 8.6
  • Exploited: added to CISA KEV 24 Apr 2024

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.

Key facts

Published
24 Apr 2024
Last changed
21 Oct 2025
Assigned by
cisco
KEV added
24 Apr 2024
KEV fix due
1 May 2024
EPSS
69.824% likely to be exploited in the next 30 days, higher than 99.381% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: yes; Technical impact: partial

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 8.6CVSS 3.1, Highfrom the CNA (cisco)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

What to do

  • Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
CiscoCisco Adaptive Security Appliance (ASA) Software
  • 9.8.1 (affected)
  • 9.8.1.5 (affected)
  • 9.8.1.7 (affected)
  • 9.8.2 (affected)
  • 9.8.2.8 (affected)
  • 9.8.2.14 (affected)
  • 9.8.2.15 (affected)
  • 9.8.2.17 (affected)
  • 9.8.2.20 (affected)
  • 9.8.2.24 (affected)
  • 9.8.2.26 (affected)
  • 9.8.2.28 (affected)
  • 9.8.2.33 (affected)
  • 9.8.2.35 (affected)
  • 9.8.2.38 (affected)
  • 9.8.3.8 (affected)
  • 9.8.3.11 (affected)
  • 9.8.3.14 (affected)
  • 9.8.3.16 (affected)
  • 9.8.3.18 (affected)
  • 9.8.3.21 (affected)
  • 9.8.3 (affected)
  • 9.8.3.26 (affected)
  • 9.8.3.29 (affected)
  • 9.8.4 (affected)
  • 9.8.4.3 (affected)
  • 9.8.4.7 (affected)
  • 9.8.4.8 (affected)
  • 9.8.4.10 (affected)
  • 9.8.4.12 (affected)
  • 9.8.4.15 (affected)
  • 9.8.4.17 (affected)
  • 9.8.4.25 (affected)
  • 9.8.4.20 (affected)
  • 9.8.4.22 (affected)
  • 9.8.4.26 (affected)
  • 9.8.4.29 (affected)
  • 9.8.4.32 (affected)
  • 9.8.4.33 (affected)
  • 9.8.4.34 (affected)
  • 9.8.4.35 (affected)
  • 9.8.4.39 (affected)
  • 9.8.4.40 (affected)
  • 9.8.4.41 (affected)
  • 9.8.4.43 (affected)
  • 9.8.4.44 (affected)
  • 9.8.4.45 (affected)
  • 9.8.4.46 (affected)
  • 9.8.4.48 (affected)
  • 9.12.1 (affected)
  • 9.12.1.2 (affected)
  • 9.12.1.3 (affected)
  • 9.12.2 (affected)
  • 9.12.2.4 (affected)
  • 9.12.2.5 (affected)
  • 9.12.2.9 (affected)
  • 9.12.3 (affected)
  • 9.12.3.2 (affected)
  • 9.12.3.7 (affected)
  • 9.12.4 (affected)
  • 9.12.3.12 (affected)
  • 9.12.3.9 (affected)
  • 9.12.2.1 (affected)
  • 9.12.4.2 (affected)
  • 9.12.4.4 (affected)
  • 9.12.4.7 (affected)
  • 9.12.4.10 (affected)
  • 9.12.4.13 (affected)
  • 9.12.4.8 (affected)
  • 9.12.4.18 (affected)
  • 9.12.4.24 (affected)
  • 9.12.4.26 (affected)
  • 9.12.4.29 (affected)
  • 9.12.4.30 (affected)
  • 9.12.4.35 (affected)
  • 9.12.4.37 (affected)
  • 9.12.4.38 (affected)
  • 9.12.4.39 (affected)
  • 9.12.4.40 (affected)
  • 9.12.4.41 (affected)
  • 9.12.4.47 (affected)
  • 9.12.4.48 (affected)
  • 9.12.4.50 (affected)
  • 9.12.4.52 (affected)
  • 9.12.4.54 (affected)
  • 9.12.4.55 (affected)
  • 9.12.4.56 (affected)
  • 9.12.4.58 (affected)
  • 9.12.4.62 (affected)
  • 9.12.4.65 (affected)
  • 9.14.1 (affected)
  • 9.14.1.10 (affected)
  • 9.14.1.6 (affected)
  • 9.14.1.15 (affected)
  • 9.14.1.19 (affected)
  • 9.14.1.30 (affected)
  • 9.14.2 (affected)
  • 9.14.2.4 (affected)
  • 9.14.2.8 (affected)
  • 9.14.2.13 (affected)
  • 9.14.2.15 (affected)
  • 9.14.3 (affected)
  • 9.14.3.1 (affected)
  • 9.14.3.9 (affected)
  • 9.14.3.11 (affected)
  • 9.14.3.13 (affected)
  • 9.14.3.18 (affected)
  • 9.14.3.15 (affected)
  • 9.14.4 (affected)
  • 9.14.4.6 (affected)
  • 9.14.4.7 (affected)
  • 9.14.4.12 (affected)
  • 9.14.4.13 (affected)
  • 9.14.4.14 (affected)
  • 9.14.4.15 (affected)
  • 9.14.4.17 (affected)
  • 9.14.4.22 (affected)
  • 9.14.4.23 (affected)
  • 9.15.1 (affected)
  • 9.15.1.7 (affected)
  • 9.15.1.10 (affected)
  • 9.15.1.15 (affected)
  • 9.15.1.16 (affected)
  • 9.15.1.17 (affected)
  • 9.15.1.1 (affected)
  • 9.15.1.21 (affected)
  • 9.16.1 (affected)
  • 9.16.1.28 (affected)
  • 9.16.2 (affected)
  • 9.16.2.3 (affected)
  • 9.16.2.7 (affected)
  • 9.16.2.11 (affected)
  • 9.16.2.13 (affected)
  • 9.16.2.14 (affected)
  • 9.16.3 (affected)
  • 9.16.3.3 (affected)
  • 9.16.3.14 (affected)
  • 9.16.3.15 (affected)
  • 9.16.3.19 (affected)
  • 9.16.3.23 (affected)
  • 9.16.4 (affected)
  • 9.16.4.9 (affected)
  • 9.16.4.14 (affected)
  • 9.16.4.18 (affected)
  • 9.16.4.19 (affected)
  • 9.16.4.27 (affected)
  • 9.16.4.38 (affected)
  • 9.16.4.39 (affected)
  • 9.16.4.42 (affected)
  • 9.16.4.48 (affected)
  • 9.16.4.55 (affected)
  • 9.17.1 (affected)
  • 9.17.1.7 (affected)
  • 9.17.1.9 (affected)
  • 9.17.1.10 (affected)
  • 9.17.1.11 (affected)
  • 9.17.1.13 (affected)
  • 9.17.1.15 (affected)
  • 9.17.1.20 (affected)
  • 9.17.1.30 (affected)
  • 9.17.1.33 (affected)
  • 9.18.1 (affected)
  • 9.18.1.3 (affected)
  • 9.18.2 (affected)
  • 9.18.2.5 (affected)
  • 9.18.2.7 (affected)
  • 9.18.2.8 (affected)
  • 9.18.3 (affected)
  • 9.18.3.39 (affected)
  • 9.18.3.46 (affected)
  • 9.18.3.53 (affected)
  • 9.18.3.55 (affected)
  • 9.18.3.56 (affected)
  • 9.18.4 (affected)
  • 9.18.4.5 (affected)
  • 9.18.4.8 (affected)
  • 9.19.1 (affected)
  • 9.19.1.5 (affected)
  • 9.19.1.9 (affected)
  • 9.19.1.12 (affected)
  • 9.19.1.18 (affected)
  • 9.19.1.22 (affected)
  • 9.19.1.24 (affected)
  • 9.19.1.27 (affected)
  • 9.20.1 (affected)
  • 9.20.1.5 (affected)
  • 9.20.2 (affected)
CiscoCisco Firepower Threat Defense Software
  • 6.2.3 (affected)
  • 6.2.3.1 (affected)
  • 6.2.3.2 (affected)
  • 6.2.3.3 (affected)
  • 6.2.3.4 (affected)
  • 6.2.3.5 (affected)
  • 6.2.3.6 (affected)
  • 6.2.3.7 (affected)
  • 6.2.3.8 (affected)
  • 6.2.3.10 (affected)
  • 6.2.3.11 (affected)
  • 6.2.3.9 (affected)
  • 6.2.3.12 (affected)
  • 6.2.3.13 (affected)
  • 6.2.3.14 (affected)
  • 6.2.3.15 (affected)
  • 6.2.3.16 (affected)
  • 6.2.3.17 (affected)
  • 6.2.3.18 (affected)
  • 6.6.0 (affected)
  • 6.6.0.1 (affected)
  • 6.6.1 (affected)
  • 6.6.3 (affected)
  • 6.6.4 (affected)
  • 6.6.5 (affected)
  • 6.6.5.1 (affected)
  • 6.6.5.2 (affected)
  • 6.6.7 (affected)
  • 6.6.7.1 (affected)
  • 6.4.0 (affected)
  • 6.4.0.1 (affected)
  • 6.4.0.3 (affected)
  • 6.4.0.2 (affected)
  • 6.4.0.4 (affected)
  • 6.4.0.5 (affected)
  • 6.4.0.6 (affected)
  • 6.4.0.7 (affected)
  • 6.4.0.8 (affected)
  • 6.4.0.9 (affected)
  • 6.4.0.10 (affected)
  • 6.4.0.11 (affected)
  • 6.4.0.12 (affected)
  • 6.4.0.13 (affected)
  • 6.4.0.14 (affected)
  • 6.4.0.15 (affected)
  • 6.4.0.16 (affected)
  • 6.4.0.17 (affected)
  • 6.7.0 (affected)
  • 6.7.0.1 (affected)
  • 6.7.0.2 (affected)
  • 6.7.0.3 (affected)
  • 7.0.0 (affected)
  • 7.0.0.1 (affected)
  • 7.0.1 (affected)
  • 7.0.1.1 (affected)
  • 7.0.2 (affected)
  • 7.0.2.1 (affected)
  • 7.0.3 (affected)
  • 7.0.4 (affected)
  • 7.0.5 (affected)
  • 7.0.6 (affected)
  • 7.0.6.1 (affected)
  • 7.1.0 (affected)
  • 7.1.0.1 (affected)
  • 7.1.0.2 (affected)
  • 7.1.0.3 (affected)
  • 7.2.0 (affected)
  • 7.2.0.1 (affected)
  • 7.2.1 (affected)
  • 7.2.2 (affected)
  • 7.2.3 (affected)
  • 7.2.4 (affected)
  • 7.2.4.1 (affected)
  • 7.2.5 (affected)
  • 7.2.5.1 (affected)
  • 7.3.0 (affected)
  • 7.3.1 (affected)
  • 7.3.1.1 (affected)
  • 7.4.0 (affected)
  • 7.4.1 (affected)

Timeline

  1. 24 Apr 2024 CVE-2024-20353 added to CISA KEV
  2. 24 Apr 2024 Added to the CISA KEV catalogue
  3. 24 Apr 2024 Published

Weakness

References