Buffer overflow in Cisco Adaptive Security Appliance Software
CVE-2026-20023
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 unauthenticated, adjacent attacker to corrupt memory on an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to memory corruption when parsing OSPF protocol packets. An attacker could exploit this vulnerability by sending crafted OSPF packets to an affected device. A successful exploit could allow the attacker to cause memory corruption causing the affected device to reboot, resulting in a DoS condition.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.002 (4.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 4.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Cisco Adaptive Security Appliance Software — versions 9.12.1, 9.12.1.2, 9.12.1.3
- Cisco Secure Firewall Adaptive Security Appliance (Asa) Software — versions 9.12.1, 9.12.1.2, 9.12.1.3
- Cisco Secure Firewall Threat Defense (Ftd) Software — versions 6.4.0, 6.4.0.1, 6.4.0.3
- Cisco Firepower Threat Defense Software — versions 6.4.0, 6.4.0.1, 6.4.0.2
- Cisco Secure Firewall Threat Defense — versions 6.4.0, 6.4.0.1, 6.4.0.2
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-20023?
- CVE-2026-20023 is a medium-severity vulnerability in Cisco Adaptive Security Appliance Software, classified under Out-of-bounds Write. CVSS score: 6.1/10. Published 2026-03-04.
- How severe is CVE-2026-20023?
- Medium severity. CVSS v3 base score is 6.1 out of 10.