CVE-2026-20073

Cisco Secure Firewall Adaptive Security Appliance Software and Cisco Secure Firewall Threat Defense Software Access Control List Bypass Vulnerability

Severity
Medium 5.8
CVSS 3.1
Exploited
Not listed
EPSS
0.004
30.8th percentile
Discovered by
Third party
Published by the vendor
Published
Mar 4, 2026
Assigned by cisco

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.

Weakness: CWE-284

Affected products

Vendor Product Category Matched by
Cisco Cisco Adaptive Security Appliance (ASA) Firewall / NGFW cna-assigner
Cisco Cisco Secure Firewall Firewall / NGFW cna-assigner
Vendor-reported affected versions (2)
  • Cisco · Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
  • Cisco · Cisco Secure Firewall Threat Defense (FTD) Software