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.

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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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