Medium [CVE-2026-20073] Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Access Control List Bypass Vulnerability
This medium-severity Cisco advisory covers CVE-2026-20073 affecting Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.2, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.3, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.4.
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Summary
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 an…
Affected products named by the advisory: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.5; and 3 more.
- Scope: At the time of publication, this vulnerability affected Cisco devices if they were running a vulnerable release of Cisco Secure Firewall ASA Software or Secure FTD Software and were deployed in a cluster configuration.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation checklist
- There are no workarounds that address this vulnerability.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
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