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, causin…
Exact source revision recorded 25 Oct 2026 14:19:22 UTC. It does not establish the source's current position. Latest evidence.
nvd · CVE-2026-59870
Publishedjs-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.
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Modified
Weakness classifications: CWE-407 · CWE-770
Original publisher date fields
published: 2026-07-08T16:16:33.580
lastModified: 2026-10-06T16:17:08.490
1 source CPE criteria · context only
- cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*
The original JSON retains the logical configuration operators, exclusions and version bounds.
- Source published
- 8 Jul 2026 16:16:33 UTC
- Source modified
- 6 Oct 2026 16:17:08 UTC
- Observed here
- 25 Oct 2026 14:19:22 UTC
- Source terms
- NIST NVD usage terms; underlying source attribution retained
Original source record · Cite this exact observation · Complete original publisher JSON
This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.
CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H