CVE-2026-59870CWE-407CWE-770denial-of-service

CVE-2026-59870

High · published July 8, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
54.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00740 · 54.1th percentile
Weaknesses
CWE-407 · Inefficient Algorithmic Complexity; CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-07-08T20:16Z
Affected products (1)
ProductVersionsFixed in
nodeca/js-yaml≥ 5.0.0, < 5.2.15.2.1
References (8)
https://github.com/nodeca/js-yaml/commit/22a8071ef032117bc6249c330b240ac3aa2d3ded · [email protected]https://github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe · [email protected]https://github.com/nodeca/js-yaml/commit/c3cc4b0bb9ddb9af2dd9b61e0d56f5ce7983cd4a · [email protected]https://github.com/nodeca/js-yaml/releases/tag/3.15.1 · [email protected]https://github.com/nodeca/js-yaml/releases/tag/4.3.1 · [email protected]https://github.com/nodeca/js-yaml/releases/tag/5.2.1 · [email protected]https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm · [email protected]https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 08 JUL 15:13Z
    js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing
    cvelistv5