CVE-2026-20020: cisco adaptive_security_appliance_software Improper Input Validation

Vulnerability summary

CVE-2026-20020 is a medium (CVSS 6.8) Improper Input Validation vulnerability in cisco adaptive_security_appliance_software. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.3% of scored vulnerabilities.

Timeline

1. 04-03-2026
   PublishedVulnerability first disclosed.
2. 04-03-2026
   Last modifiedVulnerability information updated.

Description

A vulnerability in the OSPF protocol of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. If OSPF authentication is enabled, the attacker must know the secret key to exploit this vulnerability. This vulnerability is due to insufficient input validation when processing OSPF update packets. An attacker could exploit this vulnerability by sending crafted OSPF update packets. A successful exploit could allow the attacker to create a buffer overflow, causing the affected device to reload, resulting in a DoS condition.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.