Algorithmic Complexity Affecting node-js-yaml package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.42% (34th percentile)

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  • Snyk IDSNYK-ECHOLATEST-NODEJSYAML-19498295
  • published2 Sept 2026
  • disclosed22 Jun 2026

Introduced: 22 Jun 2026

CVE-2026-53550  (opens in a new tab)
CWE-407  (opens in a new tab)

How to fix?

There is no fixed version for Echo:latest node-js-yaml.

NVD Description

Note: Versions mentioned in the description apply only to the upstream node-js-yaml package and not the node-js-yaml package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0, 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.

CVSS Base Scores

version 3.1