CVE intelligence and bounded remediation

CVE-2024-20353 — Cisco ASA and FTD Denial of Service Vulnerability

High CVSS 8.6 CISA KEV

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.

Severity
High
CVSS
8.6 (3.1)
Published
2024-04-24
CISA KEV
Known exploited
Ecosystem
operating-system
Weaknesses
CWE-835

Affected products

  • cisco / adaptive_security_appliance_software / 9.8.1
  • cisco / adaptive_security_appliance_software / 9.8.1.5
  • cisco / adaptive_security_appliance_software / 9.8.1.7
  • cisco / adaptive_security_appliance_software / 9.8.2
  • cisco / adaptive_security_appliance_software / 9.8.2.8
  • cisco / adaptive_security_appliance_software / 9.8.2.14

Showing 6 representative product identities from 267 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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