Cisco Secure Firewall Adaptive Security Appliance Software and Secure Firewall Threat Defense Software Logging Denial of Service

published 2026-09-16 last mo. modified 2026-09-18 last mo. also EUVD-2026-81128

cvss: 8.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits: 0; none known

A vulnerability in the system rate-limiting process for syslog message 419002 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 high CPU utilization on an affected device, resulting in a denial of service (DoS) condition.

This vulnerability is due to improper rate limiting for syslog message 419002. An attacker could exploit this vulnerability by sending a flood of TCP synchronization (SYN) packets to an affected device. A successful exploit could allow the attacker to cause high CPU utilization, resulting in performance degradation. 

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CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: last mo. (2026-09-18)

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected products

Cisco Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
Cisco Cisco Secure Firewall Threat Defense (FTD) Software

Classification

Weakness

CWE-835 Loop with Unreachable Exit Condition

References

sec.cloudapps.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-logging-dos-ZXXNesfN

Sources

CVE List CVE-2026-20154
NVD CVE-2026-20154

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