Summary
A vulnerability in the system rate-limiting process for syslog message 419002 of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause high CPU utilization on an affected device, resulting in a denial of service (DoS) condition.
This vulnerability is due to improper rate limiting for syslog message 419002. An attacker could exploit this vulnerability by sending a flood of TCP synchronization (SYN) packets to an affected device. A successful exploit could allow the attacker to cause high CPU utilization, resulting in performance degradation.
Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.
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.
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.
Products covered
A separate affected-products list was not included in the collected bulletin.
Remediation
There is a workaround that addresses this vulnerability. Rate limit in Cisco Secure Firewall ASA Software or Cisco Secure FTD Software using the methods described in the following sections.
Cisco Secure Firewall ASA Software
For devices that are running Cisco Secure Firewall ASA Software, append in global configuration mode and manually rate limit using the logging rate-limit 100 1 message 419002 command.
In the following example, message 419002 is limited to a rate of 100 messages per second, which will prevent successful exploitation of this vulnerability:
ASA(config)# logging rate-limit 100 1 message 419002
Cisco Secure FTD Software
For devices that are running Cisco Secure FTD Software, use one of the following options:
Choose Secure Firewall Management Center (FMC) > Devices > Platform Settings > Rate Limit > Syslog Level and deploy the appropriate policies. For more information, see Configure Logging on FTD via FMC.
Choose Firewall Device Manager (FTD) > Device > System Settings > Logging and rate limit message 419002 to 100 messages per second. For more information, see Configure and Verify Syslog in Firepower Device Manager.
While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations.
Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
Cisco considers any workarounds and mitigations (if applicable) to be temporary solutions until an upgrade to a fixed software release is available. To remediate this vulnerability 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.
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.
For instructions on upgrading a Cisco Secure FTD device, see the appropriate Cisco Secure FMC upgrade guide.
CVEs in this advisory 1
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