Denial of Service Vulnerability in Cisco Secure Firewall Products
CVE-2026-20021

4.3MEDIUM

Key Information:

Vendor

Cisco
Status
Cisco Secure Firewall Adaptive Security Appliance (asa) Software
Cisco Secure Firewall Threat Defense (ftd) Software
Vendor
CVE Published:
4 March 2026

Badges

👾 Exploit Exists

What is CVE-2026-20021?

A vulnerability exists in the OSPF protocol used by Cisco Secure Firewall Adaptive Security Appliance and Threat Defense Software. This flaw arises from inadequate input validation when processing OSPF packets, allowing an adjacent authenticated attacker to send specially crafted packets that can deplete memory resources on the affected device. The successful execution of this attack leads to a denial of service condition, impacting the device's availability and performance.

Affected Version(s)

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.2

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.3

References

https://sec.cloudapps.cisco.com/security/center/content/C...

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Adjacent Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.