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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software unknown
Version Status Constraints
9.12.3 affected —
9.12.1 affected —
9.12.2 affected —
9.12.4 affected —
9.12.3.2 affected —
9.12.3.7 affected —
9.12.2.5 affected —
9.12.3.12 affected —
9.12.1.3 affected —
9.12.2.4 affected —
9.12.1.2 affected —
9.12.2.9 affected —
9.12.3.9 affected —
9.12.2.1 affected —
9.12.4.2 affected —
9.12.4.4 affected —
9.12.4.7 affected —
9.12.4.8 affected —
9.12.4.10 affected —
9.12.4.13 affected —
9.12.4.18 affected —
9.12.4.24 affected —
9.16.1 affected —
9.12.4.26 affected —
9.16.1.28 affected —
9.12.4.29 affected —
9.16.2 affected —
9.12.4.30 affected —
9.16.2.3 affected —
9.12.4.35 affected —
9.16.2.7 affected —
9.12.4.37 affected —
9.17.1 affected —
9.16.2.11 affected —
9.16.2.13 affected —
9.12.4.39 affected —
9.12.4.38 affected —
9.16.2.14 affected —
9.17.1.7 affected —
9.12.4.40 affected —
9.16.3.3 affected —
9.16.3 affected —
9.16.3.14 affected —
9.17.1.9 affected —
9.12.4.41 affected —
9.17.1.10 affected —
9.18.1 affected —
9.12.4.47 affected —
9.16.3.15 affected —
9.18.1.3 affected —
9.17.1.11 affected —
9.12.4.48 affected —
9.18.2 affected —
9.16.3.19 affected —
9.17.1.13 affected —
9.12.4.50 affected —
9.17.1.15 affected —
9.12.4.52 affected —
9.16.3.23 affected —
9.18.2.5 affected —
9.16.4 affected —
9.12.4.54 affected —
9.17.1.20 affected —
9.18.2.7 affected —
9.19.1 affected —
9.16.4.9 affected —
9.12.4.55 affected —
9.18.2.8 affected —
9.16.4.14 affected —
9.18.3 affected —
9.19.1.5 affected —
9.12.4.56 affected —
9.17.1.30 affected —
9.19.1.9 affected —
9.18.3.39 affected —
9.16.4.19 affected —
9.12.4.58 affected —
9.19.1.12 affected —
9.18.3.46 affected —
9.16.4.27 affected —
9.19.1.18 affected —
9.18.3.53 affected —
9.18.3.55 affected —
9.16.4.38 affected —
9.17.1.33 affected —
9.12.4.62 affected —
9.16.4.39 affected —
9.18.3.56 affected —
9.20.1 affected —
9.16.4.42 affected —
9.19.1.22 affected —
9.18.4 affected —
9.20.1.5 affected —
9.18.4.5 affected —
9.19.1.24 affected —
9.16.4.48 affected —
9.18.4.8 affected —
9.20.2 affected —
9.19.1.27 affected —
9.12.4.65 affected —
9.16.4.55 affected —
9.18.4.22 affected —
9.20.2.10 affected —
9.16.4.57 affected —
9.19.1.28 affected —
9.17.1.39 affected —
9.12.4.67 affected —
9.18.4.24 affected —
9.20.2.21 affected —
9.16.4.61 affected —
9.19.1.31 affected —
9.18.4.29 affected —
9.20.2.22 affected —
9.16.4.62 affected —
9.18.4.34 affected —
9.20.3 affected —
9.16.4.67 affected —
9.16.4.70 affected —
9.18.4.40 affected —
9.23.1 affected —
9.22.1.1 affected —
9.16.4.71 affected —
9.20.3.4 affected —
9.18.4.47 affected —
9.20.3.7 affected —
9.17.1.45 affected —
9.19.1.37 affected —
9.17.1.46 affected —
9.16.4.76 affected —
9.20.3.9 affected —
9.19.1.38 affected —
9.18.4.50 affected —
9.22.1.3 affected —
9.20.3.10 affected —
9.22.1.2 affected —
9.18.4.52 affected —
9.20.3.13 affected —
9.22.1.6 affected —
9.18.4.53 affected —
9.16.4.82 affected —
9.22.2 affected —
9.19.1.42 affected —
Cisco Cisco Secure Firewall Threat Defense (FTD) Software unknown
Version Status Constraints
6.4.0.1 affected —
6.4.0.2 affected —
6.4.0.5 affected —
6.4.0 affected —
6.4.0.3 affected —
6.4.0.4 affected —
6.4.0.6 affected —
6.4.0.7 affected —
6.4.0.8 affected —
6.4.0.9 affected —
6.4.0.10 affected —
6.4.0.11 affected —
6.4.0.12 affected —
7.0.0 affected —
7.0.0.1 affected —
7.0.1 affected —
7.1.0 affected —
6.4.0.13 affected —
7.0.1.1 affected —
6.4.0.14 affected —
7.1.0.1 affected —
7.0.2 affected —
6.4.0.15 affected —
7.2.0 affected —
7.0.2.1 affected —
7.0.3 affected —
7.1.0.2 affected —
7.2.0.1 affected —
7.0.4 affected —
7.2.1 affected —
7.0.5 affected —
6.4.0.16 affected —
7.3.0 affected —
7.2.2 affected —
7.2.3 affected —
7.3.1 affected —
7.1.0.3 affected —
7.2.4 affected —
7.0.6 affected —
7.2.5 affected —
7.2.4.1 affected —
7.3.1.1 affected —
7.4.0 affected —
6.4.0.17 affected —
7.0.6.1 affected —
7.2.5.1 affected —
7.4.1 affected —
7.2.6 affected —
7.0.6.2 affected —
7.4.1.1 affected —
6.4.0.18 affected —
7.2.7 affected —
7.2.5.2 affected —
7.3.1.2 affected —
7.2.8 affected —
7.6.0 affected —
7.4.2 affected —
7.2.8.1 affected —
7.0.6.3 affected —
7.4.2.1 affected —
7.2.9 affected —
7.0.7 affected —
7.7.0 affected —
7.4.2.2 affected —
7.4.2.3 affected —
7.0.8 affected —
7.0.8.1 affected —
7.4.2.4 affected —

No data.

No data.

No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-dos-SpOFF2Re cve-icon cve-icon
History

Wed, 04 Mar 2026 17:30:00 +0000

Type Values Removed Values Added
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.
Title Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL VPN Authentication Denial of Service Vulnerability
Weaknesses CWE-244
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2026-03-04T17:17:49.841Z

Reserved: 2025-10-08T11:59:15.354Z

Link: CVE-2026-20039

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-04T18:16:17.140

Modified: 2026-03-04T18:16:17.140

Link: CVE-2026-20039

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses