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CVE-2026-59868

CVE-2026-59868 · js-yaml: YAML merge-key chains can force quadratic CPU consumption

This page contains facts from public vulnerability sources. Check the original advisory before updating.

js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.0, when merge keys are enabled, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in version 5.2.0.

CVSS 5.3 · Medium · EPSS 0.6% · Fix available

Published
Updated

Stack: system · node

Affected products and versions

  • js-yaml

    Versions
    • >= 5.0.0, < 5.2.0: Affected

    No fix published

  • js-yaml npm

    Affected ranges
    • SEMVER: ≥ 5.0.0, < 5.2.0

    Update to 5.2.0

  • node-js-yaml Ubuntu:18.04:LTS

    Versions
    • 3.9.1+dfsg-1
    • 3.10.0+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-js-yaml Ubuntu:20.04:LTS

    Versions
    • 3.13.1+dfsg-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-js-yaml Ubuntu:22.04:LTS

    Versions
    • 3.14.1+dfsg+~3.12.6-2
    • 4.1.0+dfsg+~4.0.5-4ubuntu1
    • 4.1.0+dfsg+~4.0.5-5
    • 4.1.0+dfsg+~4.0.5-6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-js-yaml Ubuntu:24.04:LTS

    Versions
    • 4.1.0+dfsg+~4.0.5-7
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-js-yaml Ubuntu:25.10

    Versions
    • 4.1.0+dfsg+~4.0.5-7
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-js-yaml Ubuntu:26.10

    Versions
    • 4.1.1+dfsg+~4.0.9-1
    • 4.2.0+~4.0.9-1
    • 4.2.0+~4.0.9-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • node-js-yaml Ubuntu:26.04:LTS

    Versions
    • 4.1.0+dfsg+~4.0.5-7
    • 4.1.1+dfsg+~4.0.9-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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