js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-59870
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-08 16:16:33 UTC
Updated2026-10-25 20:10:00 UTC
Descriptionjs-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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.007400000 probability, percentile 0.542980000 (date 2026-10-25)

Problem Types: CWE-407 | CWE-770 | CWE-407 CWE-407: Inefficient Algorithmic Complexity

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Nodeca Js-yaml All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Nodeca Js-yaml affected >= 5.0.0, < 5.2.1 Not specified
CNA Nodeca Js-yaml affected >= 3.0.0, < 3.15.1 Not specified
CNA Nodeca Js-yaml affected >= 4.0.0, < 4.3.1 Not specified

References

ReferenceSourceLinkTags
github.com/nodeca/js-yaml/releases/tag/3.15.1 [email protected] github.com
github.com/nodeca/js-yaml/releases/tag/4.3.1 [email protected] github.com
github.com/nodeca/js-yaml/commit/c3cc4b0bb9ddb9af2dd9b61e0d56f5ce7983cd4a [email protected] github.com
github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Exploit, Vendor Advisory
github.com/nodeca/js-yaml/commit/22a8071ef032117bc6249c330b240ac3aa2d3ded [email protected] github.com
github.com/nodeca/js-yaml/commit/39f3211a2f01b3c6982710cf21434ab7060acefe [email protected] github.com Patch
github.com/nodeca/js-yaml/releases/tag/5.2.1 [email protected] github.com Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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