Riskcovery

CVE-2026-20039

Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL VPN Authentication Denial of Service Vulnerability

State
Published
Severity
8.6 High
Published
Mar 4, 2026
Updated
Mar 5, 2026
Reserved
Oct 8, 2025

Read the record on cve.org

Description

A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to ineffective memory management of the VPN web server. An attacker could exploit this vulnerability by sending a large number of crafted HTTP requests to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Scores

CVSSScoreVectorSource
3.18.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hcisco

Weaknesses

  • CWE-244 Improper Clearing of Heap Memory Before Release ('Heap Inspection')

Affected Products

ProductVersions
Cisco Secure Firewall Adaptive Security Appliance (ASA) SoftwareCisco
  • 9.12.3Affected
  • 9.12.1Affected
  • 9.12.2Affected
  • 9.12.4Affected
  • 9.12.3.2Affected
  • 9.12.3.7Affected
  • 9.12.2.5Affected
  • 9.12.3.12Affected
  • 9.12.1.3Affected
  • 9.12.2.4Affected
  • 9.12.1.2Affected
  • 9.12.2.9Affected
  • 9.12.3.9Affected
  • 9.12.2.1Affected
  • 9.12.4.2Affected
  • 9.12.4.4Affected
  • 9.12.4.7Affected
  • 9.12.4.8Affected
  • 9.12.4.10Affected
  • 9.12.4.13Affected
  • 9.12.4.18Affected
  • 9.12.4.24Affected
  • 9.16.1Affected
  • 9.12.4.26Affected
  • 9.16.1.28Affected
  • and 117 more versions
Cisco Secure Firewall Threat Defense (FTD) SoftwareCisco
  • 6.4.0.1Affected
  • 6.4.0.2Affected
  • 6.4.0.5Affected
  • 6.4.0Affected
  • 6.4.0.3Affected
  • 6.4.0.4Affected
  • 6.4.0.6Affected
  • 6.4.0.7Affected
  • 6.4.0.8Affected
  • 6.4.0.9Affected
  • 6.4.0.10Affected
  • 6.4.0.11Affected
  • 6.4.0.12Affected
  • 7.0.0Affected
  • 7.0.0.1Affected
  • 7.0.1Affected
  • 7.1.0Affected
  • 6.4.0.13Affected
  • 7.0.1.1Affected
  • 6.4.0.14Affected
  • 7.1.0.1Affected
  • 7.0.2Affected
  • 6.4.0.15Affected
  • 7.2.0Affected
  • 7.0.2.1Affected
  • and 43 more versions

References

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