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node-js-yaml vulnerabilities

Vulnerabilities published for node-js-yaml in the last 30 days: 0. Listed in the KEV catalogue: 0.

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Vulnerabilities: 5

  1. CVE-2026-59868

    Medium · CVSS 5.3EPSS 0.64%No fix published

    js-yaml: YAML merge-key chains can force quadratic CPU consumption

    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.

    Published Updated
  2. CVE-2026-59869

    High · CVSS 7.5EPSS 0.58%No fix published

    js-yaml: YAML merge-key chains can force quadratic CPU consumption

    js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, 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 versions 3.15.0 and 4.3.0.

    Published Updated
  3. CVE-2026-59870

    High · CVSS 7.5EPSS 0.74%No fix published

    js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing

    js-yaml is a JavaScript YAML parser and dumper. Prior to 3.15.1, 4.3.1, and 5.2.1, YAML11_SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem() to perform a linear duplicate-key scan on every insertion, causing O(n^2) CPU consumption when yaml.load() parses a crafted ordered-map document. In v3 and v4, !!omap is active and exploitable by default. v5 doesn't use !!omap by default, and the chances of activating it are very low.This issue is fixed in 3.15.1, 4.3.1, and 5.2.1.

    Published Updated
  4. CVE-2026-53550

    Medium · CVSS 5.3EPSS 0.41%No fix published

    js-yaml: Quadratic-complexity DoS in merge key handling via repeated aliases

    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.

    Published Updated
  5. CVE-2025-64718

    Medium · CVSS 5.3EPSS 0.42%No fix published

    js-yaml has prototype pollution in merge (<<)

    js-yaml is a JavaScript YAML parser and dumper. In js-yaml before 4.1.1 and 3.14.2, it's possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (`__proto__`). All users who parse untrusted yaml documents may be impacted. The problem is patched in js-yaml 4.1.1 and 3.14.2. Users can protect against this kind of attack on the server by using `node --disable-proto=delete` or `deno` (in Deno, pollution protection is on by default).

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