Summary: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Secure Firewall Threat Defense (FTD) Software and Cisco Secure Firewall Management Center (FMC) Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. These vulnerabilities were found during internal testing. Two of them are known to be actively exploited. For more information, see the following advisories: Cisco Secure Firewall Management Center Software Static Credential Vulnerability ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-static-cred-BET3Cjh"] and Cisco Secure Firewall Management Center Software Authentication Bypass Vulnerability ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-onprem-fmc-authbypass-5JPp45V2"]. To assist customers in patching and to streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class — Common Weakness Enumeration (CWE) — and assigned a single Common Vulnerabilities and Exposures Identifier (CVE ID) to each CWE grouping. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of September 16, 2026, Security Advisories ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-notice-jfxK98ZP"].

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Vulnerable Products: These vulnerabilities affect the following Cisco products, regardless of device configuration: Secure Firewall ASA Software Secure FTD Software Secure FMC Software For information about which Cisco software releases are vulnerable, see the Fixed Software ["#fs"] section of this advisory.

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Products Confirmed Not Vulnerable: Only products listed in the Vulnerable Products ["#vp"] section of this advisory are known to be affected by these vulnerabilities.

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Details: The following table outlines the vulnerability classes that are addressed in this hardening release. The CVSS score that is assigned to each CVE ID represents the maximum potential severity of the single most impactful underlying vulnerability within that specific CWE category. CVE ID Highest CVSS Score Vulnerability Class (Highest-Level CWE) Description CVE-2026-20329 9.9 CWE-703 Improper handling of exceptional conditions (covers uncaught exceptions and reachable assertions) CVE-2026-20330 9.9 CWE-707 Incorrectly ensures that structured messages or data are well-formed and that certain security properties are met before being read from an upstream component or sent to a downstream component CVE-2026-20331 9.6 CWE-693 Incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product CVE-2026-20332 9.0 CWE-284 Improper access control (covers authorization, authentication, privileges, and bypasses)1 CVE-2026-20333 8.8 CWE-697 Incorrect comparison of two entities in a security-relevant context CVE-2026-20334 8.4 CWE-710 Improper adherence to coding standards CVE-2026-20335 8.1 CWE-682 Calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management CVE-2026-20336 7.5 CWE-664 Improper control of a resource through its lifetime (covers uninitialized variables, null pointers, and resource lifecycle issues) 1. Two vulnerabilities that belong to this vulnerability class are known to be actively exploited. For more information, see Cisco Secure Firewall Management Center Software Static Credential Vulnerability ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-static-cred-BET3Cjh"] and Cisco Secure Firewall Management Center Software Authentication Bypass Vulnerability ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-onprem-fmc-authbypass-5JPp45V2"].

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Workarounds: There are no workarounds that address these vulnerabilities.

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Fixed Software: To remediate these vulnerabilities and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory. Fixed Releases In the following table, the left column lists Cisco software releases. The center column lists hot fixes that are affected by the vulnerabilities that are described in this advisory, and the right column indicates the first software release that includes the fix for these vulnerabilities. Customers who installed one of the listed hot fix releases must install the listed first fixed release. Cisco Secure Firewall ASA Software Release Affected Hot Fix Release First Fixed Release 9.16 and earlier N/A 9.16.4.103 9.18 9.18.4.135 9.18.4.94 9.20 9.20.4.235 9.20.4.49 9.22 9.22.3.191 9.22.3.26 9.23 9.23.1.195 9.23.1.211 9.23.1.47 9.24 9.24.1.155 9.24.1.221 9.24.1.26 In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerabilities that are described in this advisory and the first release that includes the fix for these vulnerabilities. Cisco Secure FTD Software Release and Secure FMC Software Release First Fixed Release 7.0 and earlier 7.0.10 7.2 7.2.12 7.4 7.4.8 7.6 7.6.6 7.7 7.7.13 10.0 10.0.2 10.1 10.1.0 Cisco strongly recommends that customers upgrade to the first fixed releases in the preceding tables because they include fixes for multiple vulnerabilities. For more information, see Cisco Secure Firewall Adaptive Security Appliance, Secure Firewall Threat Defense, and Secure Firewall Management Center Software Hardening Release: September 2026 ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-asaftdfmc-uvpPROhN"]. The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

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Vulnerability Policy: To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy ["http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. For additional information on Cisco's vulnerability management, disclosure cadence, and software patching strategy, see Cisco's Transition to a Risk-Based Vulnerability Disclosure Model ["https://sec.cloudapps.cisco.com/security/center/resources/risk-based-disclosure"].

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Exploitation and Public Announcements: Except as otherwise noted previously, the Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

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Source: These vulnerabilities were found during internal security testing using existing testing processes as well as frontier AI models.

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Legal Disclaimer: SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT The Cisco Support and Downloads ["https://www.cisco.com/c/en/us/support/index.html"] page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid. Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC) ["https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"]. Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. When considering software upgrades ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"], customers are advised to regularly consult the advisories ["https://www.cisco.com/go/psirt"] for the relevant Cisco products to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) ["https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"] or their contracted maintenance providers. LEGAL DISCLAIMER DETAILS CISCO DOES NOT MAKE ANY EXPRESS OR IMPLIED GUARANTEES OR WARRANTIES OF ANY KIND, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, CISCO DOES NOT GUARANTEE THE ACCURACY OR COMPLETENESS OF THIS INFORMATION. THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME. Copies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories ["https://www.cisco.com/go/psirt"] page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy ["https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"] for more information.