Resource exhaustion in js-yaml (npm) - CVE-2026-59869
Published: July 3, 2026
Vulnerability identifier: #VU136867
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59869
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the js-yaml parser when parsing YAML documents containing chained merge keys. A remote attacker can send a specially crafted YAML document to cause a denial of service.
The issue results in quadratic CPU consumption for input whose size grows only linearly.
Affected software
js-yaml (npm)
Red Hat Advanced Cluster Security for Kubernetes
Red Hat Advanced Cluster Security for Kubernetes
How to mitigate CVE-2026-59869
Install security update from vendor's website.
js-yaml (npm) - addressed in versions 3.15.0, 4.3.0
Red Hat Advanced Cluster Security for Kubernetes - update to 4.11.2
Red Hat Advanced Cluster Security for Kubernetes - update to 4.11.2