Vulnerability Monitor

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CVE-2026-20021

A vulnerability in the OSPF protocol of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, adjacent attacker to exhaust memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to improperly validating input by the OSPF protocol when parsing packets. An attacker could exploit this vulnerability by by sending crafted OSPF packets to an affected device. A successful exploit could allow the attacker to exhaust memory on the affected device, resulting in a DoS condition.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 4.3, indicating it requires adjacent network access with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and limited availability for affected systems. Impacting 2 products from cisco, from cisco organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2026-03-04T19:16:12.150

Last Modified

2026-08-11T19:40:47.230

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 4.3 (MEDIUM)

Weaknesses
  • Type: Secondary
    CWE-401
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System cisco adaptive_security_appliance_software ≤ 9.12.4.67 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.16.4.85 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.17.1.46 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.18.4.68 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.19.1.42 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.20.4.14 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.22.2.14 Yes
Operating System cisco adaptive_security_appliance_software ≤ 9.23.1.22 Yes
Application cisco secure_firewall_threat_defense 6.4.0 Yes
Application cisco secure_firewall_threat_defense 6.4.0.1 Yes
Application cisco secure_firewall_threat_defense 6.4.0.2 Yes
Application cisco secure_firewall_threat_defense 6.4.0.3 Yes
Application cisco secure_firewall_threat_defense 6.4.0.4 Yes
Application cisco secure_firewall_threat_defense 6.4.0.5 Yes
Application cisco secure_firewall_threat_defense 6.4.0.6 Yes
Application cisco secure_firewall_threat_defense 6.4.0.7 Yes
Application cisco secure_firewall_threat_defense 6.4.0.8 Yes
Application cisco secure_firewall_threat_defense 6.4.0.9 Yes
Application cisco secure_firewall_threat_defense 6.4.0.10 Yes
Application cisco secure_firewall_threat_defense 6.4.0.11 Yes
Application cisco secure_firewall_threat_defense 6.4.0.12 Yes
Application cisco secure_firewall_threat_defense 6.4.0.13 Yes
Application cisco secure_firewall_threat_defense 6.4.0.14 Yes
Application cisco secure_firewall_threat_defense 6.4.0.15 Yes
Application cisco secure_firewall_threat_defense 6.4.0.16 Yes
Application cisco secure_firewall_threat_defense 6.4.0.17 Yes
Application cisco secure_firewall_threat_defense 6.4.0.18 Yes
Application cisco secure_firewall_threat_defense 7.0.0 Yes
Application cisco secure_firewall_threat_defense 7.0.0.1 Yes
Application cisco secure_firewall_threat_defense 7.0.1 Yes
Application cisco secure_firewall_threat_defense 7.0.1.1 Yes
Application cisco secure_firewall_threat_defense 7.0.2 Yes
Application cisco secure_firewall_threat_defense 7.0.2.1 Yes
Application cisco secure_firewall_threat_defense 7.0.3 Yes
Application cisco secure_firewall_threat_defense 7.0.4 Yes
Application cisco secure_firewall_threat_defense 7.0.5 Yes
Application cisco secure_firewall_threat_defense 7.0.6 Yes
Application cisco secure_firewall_threat_defense 7.0.6.1 Yes
Application cisco secure_firewall_threat_defense 7.0.6.2 Yes
Application cisco secure_firewall_threat_defense 7.0.6.3 Yes
Application cisco secure_firewall_threat_defense 7.0.7 Yes
Application cisco secure_firewall_threat_defense 7.0.8 Yes
Application cisco secure_firewall_threat_defense 7.0.8.1 Yes
Application cisco secure_firewall_threat_defense 7.1.0 Yes
Application cisco secure_firewall_threat_defense 7.1.0.1 Yes
Application cisco secure_firewall_threat_defense 7.1.0.2 Yes
Application cisco secure_firewall_threat_defense 7.1.0.3 Yes
Application cisco secure_firewall_threat_defense 7.2.0 Yes
Application cisco secure_firewall_threat_defense 7.2.0.1 Yes
Application cisco secure_firewall_threat_defense 7.2.1 Yes
Application cisco secure_firewall_threat_defense 7.2.2 Yes
Application cisco secure_firewall_threat_defense 7.2.3 Yes
Application cisco secure_firewall_threat_defense 7.2.4 Yes
Application cisco secure_firewall_threat_defense 7.2.4.1 Yes
Application cisco secure_firewall_threat_defense 7.2.5 Yes
Application cisco secure_firewall_threat_defense 7.2.5.1 Yes
Application cisco secure_firewall_threat_defense 7.2.5.2 Yes
Application cisco secure_firewall_threat_defense 7.2.6 Yes
Application cisco secure_firewall_threat_defense 7.2.7 Yes
Application cisco secure_firewall_threat_defense 7.2.8 Yes
Application cisco secure_firewall_threat_defense 7.2.8.1 Yes
Application cisco secure_firewall_threat_defense 7.2.9 Yes
Application cisco secure_firewall_threat_defense 7.2.10 Yes
Application cisco secure_firewall_threat_defense 7.2.10.2 Yes
Application cisco secure_firewall_threat_defense 7.3.0 Yes
Application cisco secure_firewall_threat_defense 7.3.1 Yes
Application cisco secure_firewall_threat_defense 7.3.1.1 Yes
Application cisco secure_firewall_threat_defense 7.3.1.2 Yes
Application cisco secure_firewall_threat_defense 7.4.0 Yes
Application cisco secure_firewall_threat_defense 7.4.1 Yes
Application cisco secure_firewall_threat_defense 7.4.1.1 Yes
Application cisco secure_firewall_threat_defense 7.4.2 Yes
Application cisco secure_firewall_threat_defense 7.4.2.1 Yes
Application cisco secure_firewall_threat_defense 7.4.2.2 Yes
Application cisco secure_firewall_threat_defense 7.4.2.3 Yes
Application cisco secure_firewall_threat_defense 7.4.2.4 Yes
Application cisco secure_firewall_threat_defense 7.4.3 Yes
Application cisco secure_firewall_threat_defense 7.6.0 Yes
Application cisco secure_firewall_threat_defense 7.6.1 Yes
Application cisco secure_firewall_threat_defense 7.6.2 Yes
Application cisco secure_firewall_threat_defense 7.6.2.1 Yes
Application cisco secure_firewall_threat_defense 7.7.0 Yes
Application cisco secure_firewall_threat_defense 7.7.10 Yes
Application cisco secure_firewall_threat_defense 7.7.10.1 Yes
References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For cisco's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.