Is js-yaml 4.2 vulnerable?
npm · 1 release from 4.2.0 to 4.2.0 · latest js-yaml is 5.5.0 · checked 1 Nov 2026
Yes: 3 known advisories
Yes. js-yaml 4.2.0, the last 4.2 release, is affected by 3 known security advisories (3 high), including CVE-2026-84375, CVE-2026-59869. Upgrade to 4.3.2 or later to fix all of them.
npm install js-yaml@4.3.2Advisories affecting js-yaml 4.2.0
js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sources
- Affected
- >=4.0.0 <4.3.2 · >=3.0.0 <3.15.2
- Fixed in
- 3.15.2, 4.3.2
JS-YAML: Quadratic CPU consumption in !!omap resolution (3.x and 4.x) — CVE-2026-59870 fix not backported
- Affected
- >=4.0.0 <4.3.1 · >=3.0.0 <3.15.1
- Fixed in
- 3.15.1, 4.3.1
js-yaml: YAML merge-key chains can force quadratic CPU consumption
- Affected
- >=3.0.0 <3.15.0 · >=4.0.0 <4.3.0
- Fixed in
- 3.15.0, 4.3.0
Which of your client projects are still on js-yaml 4.2?
NPMscan reads the lockfiles in every GitHub repo you pick, finds the exact js-yaml version each one installs, and checks it against these advisories. Each finding comes with the command that fixes it.
Other js-yaml versions
Advisory data from OSV.dev (opens OSV.dev in a new tab), which includes the GitHub Advisory Database. Release list from the npm registry. Refreshed daily.