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Fencer Vulns
medium 5.8

CVE-2024-20481 kev in the critical feed json

A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Def…

published 2024-10-23 2 y ago modified 2026-08-11 2 mo ago also EUVD-2024-18196

cvss
5.8
version 3.1, CNA
cisa kev
Exploited
added 2024-10-24
epss
15.9%
EPSS 15.9% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

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.

Patch / fix

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

Timeline

  1. Published
  2. Added to CISA KEV
  3. CISA SSVC: exploitation active
  4. CISA patch deadline

Known exploited

Added
2 y ago
Patch by
2024-11-14 (23 mo ago)
Ransomware
Not known
Required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vendor, product
Cisco, Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
CISA name
Cisco ASA and FTD Denial-of-Service Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

15.88% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
NVD 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Affected products

  • Cisco Cisco Adaptive Security Appliance (ASA) Software
  • Cisco Cisco Firepower Threat Defense Software
  • cisco adaptive_security_appliance_software
  • cisco firepower_threat_defense_software

Classification

Weakness
  • CWE-772 Missing Release of Resource after Effective Lifetime

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.