Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability

SecurityVulns
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A vulnerability in the certificate processing 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 the device to reload unexpectedly, resulting in a denial of service (DoS) condition.<br><br>
This vulnerability is due to improper parsing of&nbsp;SSL/TLS certificates. An attacker could exploit this vulnerability by sending a crafted SSL/TLS certificate to an affected system through a listening SSL/TLS socket. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.<br><br>

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.<br><br>
This advisory is available at the following link:<br><a href=”https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ssltls-dos-eHw76vZe”>https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ssltls-dos-eHw76vZe</a><br><br>

This advisory is part of the August 2025 release of the Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see <a href=”https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75415″>Cisco Event Response: August 2025 Semiannual Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication</a>.<br><br>

<br/>Security Impact Rating: High

<br/>CVE: CVE-2025-20134Cisco Security AdvisoryRead More