Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
CVE-2026-59870
nodeca js-yaml — js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing
AV AC PR UI S C I A CVSS EPSS %ile KEV
N L N N U N N H 7.5 .0074 53.7 —
AFFECTED
Product Versions Fixed
js-yaml >= 5.0.0, < 5.2.1 – —
TIMELINE
Jul 7 Reserved by GitHub_M
Jul 8 EXPLOIT PUBLISHED — CVE-2026-59870 (nodeca js-yaml). Public exploit reference added.
Jul 8 Published (CNA: GitHub_M)
Oct 6 EXPLOIT PUBLISHED — CVE-2026-59870 (nodeca js-yaml). Public exploit reference added.
Description
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.
Lifecycle
Complete event history — 4 events, chronological
| Date | Event | Detail |
|---|
| July 7, 2026 | Reserved | Reserved by GitHub_M |
| July 8, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-59870 (nodeca js-yaml). Public exploit reference added. |
| July 8, 2026 | Published | Published (CNA: GitHub_M) |
| October 6, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-59870 (nodeca js-yaml). Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| nodeca | js-yaml | — | >= 5.0.0, < 5.2.1 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-59870 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
