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Vulnerability record · CVE-2026-20073 · published 4 March 2026

CVE-2026-20073: Cisco adaptive security appliance software improper access control vulnerability

Cisco · Adaptive Security Appliance Software

A vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should be denied through an affected device. This vulnerability is due to improper error handling when an affected device that is joining a cluster runs out of memory while replicating access control rules. An attacker could exploit this vulnerability by sending traffic that should be blocked through the device. A successful exploit could allow the attacker to bypass access controls and reach devices in protected networks.

5.8 CVSS 3.1 Medium EPSS 0.38% · top 70.5% CWE-284 · Improper access control
5.8CVSS 3.1 base score
0.38%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
1References
11 Aug 2026Last modified by NVD

Description

A vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should be denied through an affected device. This vulnerability is due to improper error handling when an affected device that is joining a cluster runs out of memory while replicating access control rules. An attacker could exploit this vulnerability by sending traffic that should be blocked through the device. A successful exploit could allow the attacker to bypass access controls and reach devices in protected networks.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-aclbypass-dos-CVxVRSvQ Vendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-20073), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.