Denial of Service Vulnerability in Cisco Secure Firewall Products
CVE-2025-20134

8.6HIGH

Key Information:

Vendor

Cisco
Status
Cisco Adaptive Security Appliance (asa) Software
Cisco Firepower Threat Defense Software
Vendor
CVE Published:
14 August 2025

Badges

👾 Exploit Exists

What is CVE-2025-20134?

A vulnerability in the SSL/TLS certificate processing of Cisco's Secure Firewall Adaptive Security Appliance and Threat Defense Software can be exploited by an unauthenticated remote attacker. By sending a specially crafted SSL/TLS certificate to a vulnerable system via a listening socket, the attacker could trigger an unexpected device reload. This incident results in a denial of service (DoS), affecting system availability and disrupting network operations.

Affected Version(s)

Cisco Adaptive Security Appliance (ASA) Software 9.12.4.39

Cisco Adaptive Security Appliance (ASA) Software 9.12.4.40

Cisco Adaptive Security Appliance (ASA) Software 9.14.4.6

References

https://sec.cloudapps.cisco.com/security/center/content/C...

CVSS V3.1

Score:
8.6
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Changed

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

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CVE-2025-20134 : Denial of Service Vulnerability in Cisco Secure Firewall Products