Is CVE-2026-20023 being actively exploited?

CVE-2026-20023 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2026-20023?

CVE-2026-20023 has a CVSS 3.1 base score of 6.1 (MEDIUM).

CVE-2026-20023

MEDIUM · CVSS 6.1EPSS 0.2%EU EUVD

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.

Key facts

CVSS score: 6.1 (v3.1)
Severity: MEDIUM
CVSS vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness (CWE): CWE-787
EPSS score: 0.2% (5th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2026-9480)
Published: March 4, 2026
NVD last modified: August 11, 2026
Status: Analyzed

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2026-9480 in the EU Vulnerability Database. Last updated in EUVD on March 4, 2026.

View on the EU Vulnerability Database

Affected products

cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
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cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
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cisco / adaptive security appliance software
cisco / adaptive security appliance software
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cisco / adaptive security appliance software
cisco / adaptive security appliance software
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cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
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cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software
cisco / adaptive security appliance software

and 184 more…

Certified products that may be affected

2 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Cisco Secure Firewall Threat Defense (FTD) 7.4 with Secure Firewall Management Center (FMC) 7.4 and Secure Client 5.1 - Cisco Systems, Inc. - Common Criteria NSCIB-CC-2400046-01-CR - active
Cisco Secure Firewall Threat Defense Virtual 7.4 with FMC/FMCv - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-11510-2025 - active

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ospf-ZH8PhbSW(Vendor Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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