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8.6
HIGH CVSS 3.1
CVE-2025-20134
Cisco Adaptive Security Appliance and Firepower Threat Defense Software SSL/TLS Certificate Denial of Service Vulnerability
Description

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. This vulnerability is due to improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

INFO

Published Date :

Aug. 14, 2025, 5:15 p.m.

Last Modified :

Aug. 19, 2025, 10:15 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2025-20134 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco adaptive_security_appliance_software
2 Cisco firepower_threat_defense
: Total Affected Vendor : 1 | Products : 2
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH [email protected]
Solution
Update Cisco software and adjust DNS inspection on NAT rules to prevent denial of service.
  • Update Cisco Secure Firewall ASA Software to the latest version.
  • Update Cisco Secure Firewall FTD Software to the latest version.
  • Disable DNS inspection on static NAT rules if applicable.
  • Review and adjust NAT rules to avoid DNS inspection.
Public PoC/Exploit Available at Github

CVE-2025-20134 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-20134.

URL Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ssltls-dos-eHw76vZe
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-20134 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-20134 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
Rat5ak/Anatomy-of-a-Reconnaissance-Campaign-Deconstructing-Bullet-Proof-Host---AS401116-AS401120-AS215540

Anatomy of a Reconnaissance Campaign: Deconstructing the Bulletproof Hosting Ecosystem of AS401116, AS401120, and AS215540

Updated: 5 days, 8 hours ago
1 stars 0 fork 0 watcher
Born at : Aug. 29, 2025, 7:18 p.m. This repo has been linked 5 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-20134 vulnerability anywhere in the article.

  • BleepingComputer
Cisco warns of max severity flaw in Firewall Management Center

Cisco is warning about a critical remote code execution (RCE) vulnerability in the RADIUS subsystem of its Secure Firewall Management Center (FMC) software. Cisco FCM is a management platform for the ... Read more

Published Date: Aug 15, 2025 (2 weeks, 6 days ago)
  • The Hacker News
Cisco Warns of CVSS 10.0 FMC RADIUS Flaw Allowing Remote Code Execution

Aug 15, 2025Ravie LakshmananVulnerability / Network Security Cisco has released security updates to address a maximum-severity security flaw in Secure Firewall Management Center (FMC) Software that ... Read more

Published Date: Aug 15, 2025 (2 weeks, 6 days ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-20134 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Aug. 19, 2025

    Action Type Old Value New Value
    Changed Description 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. This vulnerability is due to improper parsing of 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. 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. This vulnerability is due to improper parsing of SSL/TLS certificates. An attacker could exploit this vulnerability by sending crafted DNS packets that match a static Network Address Translation (NAT) rule with DNS inspection enabled through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
  • New CVE Received by [email protected]

    Aug. 14, 2025

    Action Type Old Value New Value
    Added Description 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. This vulnerability is due to improper parsing of 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
    Added CWE CWE-415
    Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ssltls-dos-eHw76vZe
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 8.6
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact