Cisco
CVE-2026-20073
MEDIUM
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Unauthenticated remote attackers can bypass firewall access controls on Cisco Secure Firewall ASA and FTD devices by exploiting improper error handling during cluster memory exhaustion when syncing security rules. This allows attackers to send traffic that should be blocked through affected devices to reach protected networks. No patch is currently available.
Technical ContextAI
Classified as CWE-284 (Improper Access Control). 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 bl
RemediationAI
Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.
Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today