js-yaml

5.5.0 · 15 Oct 2026MIT322.7M / weekRepository Homepage npm Atom feed

Same major only

1 release in betweenevery note read

Other targets from 5.1.0Newest 5.x, Latest5.5.0 Clears its 4 advisories5.4.1

1
change to make: 1
advisory fixed: 2
new: 1
fix

Before you upgrade

Tick each one off as you go

maxMergeSeqLength replaced with maxTotalMergeKeys for limiting YAML merge processing.
breaking5.2.0

Security

3 advisories still affect 5.2.0

js-yaml: Exponential parsing time in flow collections leads to denial of servicehigh · GHSA-pm4m-ph32-ghv5
js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sourcesmoderate · GHSA-r3ph-w7gj-g6xm
js-yaml: Quadratic-complexity (O(n^2)) DoS via !!omap tag in YAML11_SCHEMAmoderate · GHSA-724g-mxrg-4qvm

Upgrading to 5.4.1 clears them.

Fixes 1 advisory affecting 5.1.0

js-yaml: YAML merge-key chains can force quadratic CPU consumption in js-yamlmoderate · GHSA-g796-fgmg-93mv

Release by release

5.2.0
26 Jun 20262 new · 1 fix
- new
  Added maxTotalMergeKeys (10000) loader option to limit the total number of keys processed by YAML merge (<<) across one load() / loadAll() call.
- new
  Added maxAliases (-1) loader option to limit the number of YAML aliases per document.
- fixed
  Round-trip of integers with exponential form (>= 1e21)

Upgrade to 5.2.0

npm install js-yaml@5.2.0

What 5.2.0 needs

Reading 5.2.0's manifest…

Check against your package.json

Which of your other dependencies stand in the way of 5.2.0. Read once, not stored.

After upgrading

Run the type checker, the linter and the tests.
Build, and look for new deprecation warnings.
Update peer dependencies the new version asks for.
3 advisories still affect 5.2.0.