Denial of Service Vulnerability in Cisco Secure Firewall Products
CVE-2026-20154

8.6HIGH

Key Information:

Vendor

Cisco
Status
Cisco Secure Firewall Adaptive Security Appliance (asa) Software
Cisco Secure Firewall Threat Defense (ftd) Software
Vendor
CVE Published:
16 September 2026

Badges

👾 Exploit Exists

What is CVE-2026-20154?

A vulnerability exists in the rate-limiting process for syslog messages in Cisco Secure Firewall ASA and FTD Software, allowing unauthenticated remote attackers to potentially exploit it. By sending a barrage of TCP SYN packets, an attacker could instigate excessive CPU usage on the device, leading to significant performance degradation and potentially denying service to legitimate users. Addressing this vulnerability is crucial to maintaining system performance and availability.

Affected Version(s)

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.1

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.1.28

Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2

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

.