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Vulnerabilities

Vulnerability · CVE-2024-20481

Cisco ASA and FTD Denial-of-Service Vulnerability

Published Oct 23, 2024 · catalog updated Aug 11, 2026 · Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)

Patch now

CVE-2024-20481 is in the CISA known-exploited catalog, due Nov 14, 2024. Confirm Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Medium5.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
15.87%
Remediation
Remediation guidance
Affected products
cpe cisco/adaptive security appliance software · cpe cisco/secure firewall threat defense · vendor Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)

A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service. This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authentication requests to an affected device. A successful exploit could allow the attacker to exhaust resources, resulting in a DoS of the RAVPN service on the affected device. Depending on the impact of the attack, a reload of the device may be required to restore the RAVPN service. Services that are not related to VPN are not affected. Cisco Talos discussed these attacks in the blog post Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/adaptive security appliance software9.8.1
  • cpe cisco/secure firewall threat defense6.2.3
  • cpe cisco/secure firewall threat defense6.2.3.1
  • cpe cisco/secure firewall threat defense6.2.3.2
  • cpe cisco/secure firewall threat defense6.2.3.3
  • cpe cisco/secure firewall threat defense6.2.3.4
  • cpe cisco/secure firewall threat defense6.2.3.5
  • cpe cisco/secure firewall threat defense6.2.3.6
  • cpe cisco/secure firewall threat defense6.2.3.7
  • vendor Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)version unspecified

How to fix CVE-2024-20481

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2024-20481 is in the CISA known-exploited catalog, due Nov 14, 2024. Confirm Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with cisco/adaptive security appliance software 9.8.1; cisco/secure firewall threat defense 6.2.3; cisco/secure firewall threat defense 6.2.3.1; cisco/secure firewall threat defense 6.2.3.2. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-772: Missing Release of Resource after Effective Lifetime. EPSS 15.87%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 23, 2024 · Catalog

    Detected

    A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service. This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authenti

  2. Oct 24, 2024 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  3. Nov 14, 2024 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  4. Aug 11, 2026 · Catalog

    Updated

    A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service. This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authenti

Sources

  • CISA KEVConfirmed exploitationCVE-2024-20481

    Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain a missing release of resource after effective lifetime vulnerability that could allow an unauthenticated, remote attacker to cause a denial-of-service (DoS) of the RAVPN service.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2024-20481

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2024-20481

    30-day exploitation probability 15.9%

    first.org
  • NIST NVDVulnerability recordCVE-2024-20481

    A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service. This vulnerab

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2024-20481

    Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain a missing release of resource after effective lifetime vulnerability that could allow an unauthenticated, remote attacker to cause a denial-of-service (DoS) of the RAVPN service.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.