CVE-2024-20353

CVE-2024-20353 is a high-severity vulnerability in Cisco Adaptive Security Appliance Software with a CVSS 3.x base score of 8.6. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2024-04-24). The underlying weakness is classified as CWE-835.

Key facts

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.

Frequently asked questions

What is 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.
How severe is CVE-2024-20353?
CVE-2024-20353 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-20353 being actively exploited?
Yes. CVE-2024-20353 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2024-04-24, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2024-20353?
CVE-2024-20353 primarily affects Cisco Adaptive Security Appliance Software. In total, 267 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-20353?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2024-20353 have an EU (EUVD) identifier?
Yes. CVE-2024-20353 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-18068. It is also flagged as exploited in the EUVD (since 2024-04-24).
When was CVE-2024-20353 published?
CVE-2024-20353 was published on 2024-04-24 and last updated on 2026-06-17.

References

Affected products (267)

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