VULNERABILITY INTELLIGENCE

CVE-2026-53550

CVSS score5.3 MEDIUM
EPSS probability0.41%
CISA KEVNot currently listed
Published2026-06-22
Last modified2026-10-25
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Description

js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.

Weakness classification

  • security-advisories@github.com: CWE-407

Primary references