CVE-2026-53550 (Medium) detected in js-yaml-3.14.0.tgz

[mend-bolt-for-github]

CVE-2026-53550 - Medium Severity Vulnerability

Vulnerable Library - js-yaml-3.14.0.tgz

YAML 1.2 parser and serializer

Library home page: https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.0.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/js-yaml/package.json

Dependency Hierarchy:

• nuxt-2.14.3.tgz (Root Library)
  • webpack-2.14.3.tgz
    • cssnano-4.1.10.tgz
      • cosmiconfig-5.2.1.tgz
        • ❌ js-yaml-3.14.0.tgz (Vulnerable Library)

Found in HEAD commit: de1c2b0d1a23367b161c2d995029f9693bd8a155

Found in base branch: master

Vulnerability Details

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.

Publish Date: 2026-06-22

URL: CVE-2026-53550

CVSS 3 Score Details (5.3)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: None
  • Integrity Impact: None
  • Availability Impact: Low

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Release Date: 2026-06-15

Fix Resolution: https://github.com/nodeca/js-yaml.git - 4.2.0

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