Inefficient Algorithmic Complexity in js-yaml (npm) - #VU140667
Published: August 1, 2026
Vulnerability identifier: #VU140667
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: N/A
CWE-ID: CWE-407
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 inefficient algorithmic complexity in resolveYamlOmap() when parsing untrusted YAML containing !!omap sequences. A remote attacker can send a specially crafted YAML document to cause a denial of service.
The issue is reachable through yaml.load() with the default schema, and the synchronous processing blocks the Node.js event loop for the duration of parsing.
Affected software
js-yaml (npm)
Remediation
Install security update from vendor's website.
js-yaml (npm) - addressed in versions 3.15.1, 4.3.1