CVE & CISA-KEV Catalog

CVE-2026-20154

HIGH
8.6
CVSS v3
NVD

Description

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.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploit Intelligence

EPSS data unavailable for this CVE.

References

Other references1

Related Vulnerabilities

Other CWE-835 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2020-13935High7.587%-Fix
CVE-2020-36227High7.578%-Fix
CVE-2022-0778High7.573%-Fix
CVE-2024-20353High8.671%KEV-
CVE-2019-14241High7.570%--
CVE-2017-16944High7.563%-Fix

Common questions

How do I fix CVE-2026-20154?

No published fix for CVE-2026-20154 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

How severe is CVE-2026-20154?

CVE-2026-20154 has a CVSS v3 base score of 8.6, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-18.