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9.6

Cisco Secure Firewall software may bypass security checks

CVE-2026-20331 · published 26 days ago
Summary

Cisco’s Adaptive Security Appliance, Threat Defense, and Management Center software could fail to enforce their own protection rules, allowing malicious traffic to pass unchecked. This weakness could let attackers compromise your network or gain unauthorized access. Apply the latest Cisco hardening update as soon as possible to restore proper protection.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
VendorProductAffected versions
cisco cisco secure firewall adaptive security appliance (asa) software 9.16.1
cisco cisco secure firewall management center (fmc) 7.0.0
cisco cisco secure firewall threat defense (ftd) software 7.0.0.1
Original advisory text
Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Protection Mechanism Failure Vulnerabilities
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities.  

The vulnerabilities tracked by CVE-2026-20331 are related to the failure of protection mechanisms issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-693.
References
Fix within
Internet-facing 14 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker full control
Severity
9.6 Critical
Exploitation
<1% chance of attack within 30 days
Type
CWE-693Protection Mechanism Failure
Timeline
Published16 Sep 2026
Updated7 Oct 2026
First seen16 Sep 2026
Sources
CVE-2026-20331 · NVD
CVE-2026-20331 · MITRE
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