Cisco Security Advisory
Click Icon to Copy Verbose Score
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:X/RL:X/RC:X
-
Multiple vulnerabilities in Cisco Secure Firewall Management Center (FMC) Software could allow a remote attacker to gain root access, download sensitive files, perform a SQL injection attack, or cause a denial of service (DoS) condition.
For more information about these vulnerabilities, see the Details section of this advisory.
Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fmc-mulivulns-4PsnFwvxThis 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. In addition, for further documentation of improvements and fixes in Cisco Secure Firewall products, see Cisco Secure Firewall Adaptive Security Appliance Software, Secure Firewall Threat Defense Software, and Secure Firewall Management Center Software Hardening Release: September 2026.
-
Vulnerable Products
CVE-2026-20341: This vulnerability affects Cisco Secure FMC Software, regardless of device configuration. The attacker must have root access on a managed Cisco Firepower Threat Defense (FTD) device.
CVE-2026-20340 and CVE-2026-20342: These vulnerabilities affect Cisco Secure FMC Software, regardless of device configuration. The attacker must have the ability to log in as a low-privilege user, such as the Security Analyst role.
CVE-2026-20343 and CVE-2026-20344: These vulnerabilities affect Cisco Secure FMC Software, regardless of device configuration.
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.
Cisco has confirmed that these vulnerabilities do not affect the following Cisco products:
- Secure Firewall Adaptive Security Appliance (ASA) Software
- Secure Firewall Threat Defense (FTD) Software
-
The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit another vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerabilities.
Details about the vulnerabilities are as follows:
CVE-2026-20341: Cisco Secure FMC Software sftunnel Deserialization Root Command Execution Vulnerability
A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges.
This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer.
To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu16954
CVE ID: CVE-2026-20341
Security Impact Rating (SIR): Critical
CVSS Base Score: 9.1
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:HCVE-2026-20340: Cisco Secure FMC Software Deserialization Arbitrary Root Command Execution Vulnerability
A vulnerability in Cisco Secure FMC Software could allow an authenticated, remote attacker to execute arbitrary commands at the root privilege level.
This vulnerability is due to unsecured deserialization of web-management user-controlled data. An attacker could exploit this vulnerability by authenticating to the device and sending a crafted HTTP payload. A successful exploit could allow the attacker to save the crafted payload and then execute it on the underlying operating system as root.
To exploit this vulnerability, the attacker must have valid credentials for a user account with at least the role of Security Analyst (read-only).
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu27275
CVE ID: CVE-2026-20340
Security Impact Rating (SIR): High
CVSS Base Score: 8.8
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVE-2026-20344: Cisco Secure FMC Software SQL Injection Vulnerability
A vulnerability in the web-based management interface of Cisco Secure FMC Software could allow an authenticated, remote attacker to perform a SQL injection attack against an affected device. To exploit this vulnerability, the attacker must have a valid account on the device with the role of Security Approver, Access Admin, or Network Admin.
This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain any data from the database, obtain the session credentials of an authenticated Administrator, and take actions with administrative privileges on the affected device.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu24501
CVE ID: CVE-2026-20344
Security Impact Rating (SIR): High
CVSS Base Score: 8.8
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVE-2026-20342: Cisco Secure FMC Software Arbitrary File Download Vulnerability
A vulnerability in a specific file download API of Cisco Secure FMC Software could allow an authenticated, remote attacker to download arbitrary files from an affected system.
This vulnerability exists because user input is not being sanitized. An attacker could exploit this vulnerability by sending a crafted HTTPS request. A successful exploit could allow the attacker to download arbitrary files from the affected system.
To exploit this vulnerability, the attacker must have valid credentials for a user account with at least the role of Security Analyst (read-only).
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu42586
CVE ID: CVE-2026-20342
Security Impact Rating (SIR): High
CVSS Base Score: 7.7
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:NCVE-2026-20343: Cisco Secure FMC Software Information Disclosure and Disk DoS Vulnerability
A vulnerability in a critical API for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to download sensitive files and use unbounded disk space.
This vulnerability exists because a critical API lacks authentication. An attacker could exploit this vulnerability by repeatedly invoking the API. A successful exploit could allow the attacker to download sensitive files that should be restricted and consume disk space so the device could become unresponsive, causing a DoS condition.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwu36643
CVE ID: CVE-2026-20343
Security Impact Rating (SIR): High
CVSS Base Score: 7.5
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
-
There are no workarounds that address these vulnerabilities.
-
Cisco considers any workarounds and mitigations (if applicable) to be temporary solutions until an upgrade to a fixed software release is available. 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.
Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software
To help customers determine their exposure to vulnerabilities in Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software, Cisco provides the Cisco Software Checker. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”).
To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to search for vulnerabilities that affect a specific software release. To use the form, follow these steps:
- Choose which advisories the tool will search—all advisories, only advisories with a Critical or High Security Impact Rating (SIR), or only this advisory.
- Choose the appropriate software.
- Choose the appropriate platform.
- Enter a release number—for example, 9.20.3.4 for Cisco Secure Firewall ASA Software or 7.4.2 for Cisco Secure FTD Software.
- Click Check.
Additional Resources
For help determining the best Cisco Secure Firewall ASA, Secure FMC, or Secure FTD Software release, see the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.
Cisco Secure Firewall ASA Compatibility
Cisco Secure Firewall ASA Upgrade Guide
Cisco Secure Firewall Threat Defense Compatibility Guide
-
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
-
Cisco would like to thank Christophe Schleypen from the NATO Cyber Security Centre (NCSC) for reporting these vulnerabilities.
-
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. 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.
-
Show LessVersion Description Section Status Date 1.0 Initial public release. — Final 2026-SEP-16
-
SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT
The Cisco Support and Downloads 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). 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, customers are advised to regularly consult the advisories 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) 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 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 for more information.