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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-20073

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.

MEDIUM 5.8EPSS 0.38%

Does this matter?

Lower severity and a low EPSS score (0.38%). Track it; it rarely justifies an emergency change on its own.

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
5.8 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
EPSS
0.38% probability · 32th percentile
CISA KEV
Not listed
Weakness
CWE-284
Affected
cisco/adaptive security appliance software · cisco/secure firewall threat defense
Source
psirt@cisco.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.