Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Adaptive Security Appliance Software | >= 9.12.1, <= 9.12.4.67 |
| Cisco | Firepower Threat Defense Software | 6.4.0 |
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-20021?
CVE-2026-20021 is a vulnerability with a CVSS score of 4.3 (MEDIUM). 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 ...
How severe is CVE-2026-20021?
CVE-2026-20021 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-20021?
Check the references section above for vendor advisories and patch information. Affected products include: Cisco Adaptive Security Appliance Software, Cisco Firepower Threat Defense Software.