High
node-js-yaml — security advisory
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.
- Products
- node-js-yaml
- Affected versions
- 3.10.0+dfsg-1, 3.13.1+dfsg-2, 3.14.1+dfsg+~3.12.6-2, 3.9.1+dfsg-1, 4.1.0+dfsg+~4.0.5-4ubuntu1, 4.1.0+dfsg+~4.0.5-5, 4.1.0+dfsg+~4.0.5-6, 4.1.0+dfsg+~4.0.5-7, 4.1.1+dfsg+~4.0.9-1, 4.2.0+~4.0.9-1, 4.2.0+~4.0.9-2
- Fixed versions
- Not specified
- CVEs
- CVE-2026-59870
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:10 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-59870
node-js-yaml
Fixed versions: Not specified
node-js-yaml
Fixed versions: Not specified
node-js-yaml
Fixed versions: Not specified
node-js-yaml
Fixed versions: Not specified
node-js-yaml
Fixed versions: Not specified
node-js-yaml
Fixed versions: Not specified
node-js-yaml
Fixed versions: Not specified
Complete source record
{
"id": "f6d8c36c93a44d2b5c0aa12bf03436ef35c2cf0ddb5adf9b1a2c3cba5a72042f",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-59870",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-59870",
"summary": "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.",
"evidence": "osv:UBUNTU-CVE-2026-59870",
"products": [
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.9.1+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.10.0+dfsg-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.13.1+dfsg-2",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.14.1+dfsg+~3.12.6-2",
"evidence": "/affected/2/versions"
},
{
"value": "4.1.0+dfsg+~4.0.5-4ubuntu1",
"evidence": "/affected/2/versions"
},
{
"value": "4.1.0+dfsg+~4.0.5-5",
"evidence": "/affected/2/versions"
},
{
"value": "4.1.0+dfsg+~4.0.5-6",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.1.0+dfsg+~4.0.5-7",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.1.0+dfsg+~4.0.5-7",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.1.1+dfsg+~4.0.9-1",
"evidence": "/affected/5/versions"
},
{
"value": "4.2.0+~4.0.9-1",
"evidence": "/affected/5/versions"
},
{
"value": "4.2.0+~4.0.9-2",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
"value": "node-js-yaml",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.1.0+dfsg+~4.0.5-7",
"evidence": "/affected/6/versions"
},
{
"value": "4.1.1+dfsg+~4.0.9-1",
"evidence": "/affected/6/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-59870",
"aliases": [
"UBUNTU-CVE-2026-59870"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"3.9.1+dfsg-1",
"3.10.0+dfsg-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "3.10.0+dfsg-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"3.13.1+dfsg-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "3.13.1+dfsg-2"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"3.14.1+dfsg+~3.12.6-2",
"4.1.0+dfsg+~4.0.5-4ubuntu1",
"4.1.0+dfsg+~4.0.5-5",
"4.1.0+dfsg+~4.0.5-6"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "4.1.0+dfsg+~4.0.5-6"
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},
{
"ranges": [
{
"type": "ECOSYSTEM",
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],
"package": {
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"4.1.0+dfsg+~4.0.5-7"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
"binaries": [
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},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"4.1.0+dfsg+~4.0.5-7"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
"binaries": [
{
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]
}
},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"4.1.1+dfsg+~4.0.9-1",
"4.2.0+~4.0.9-1",
"4.2.0+~4.0.9-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "4.2.0+~4.0.9-2"
}
]
}
},
{
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],
"package": {
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"purl": "pkg:deb/ubuntu/node-js-yaml?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"4.1.0+dfsg+~4.0.5-7",
"4.1.1+dfsg+~4.0.9-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-59870.json"
},
"ecosystem_specific": {
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{
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}
]
}
}
],
"modified": "2026-10-17T13:00:28.502170865Z",
"provider": "osv",
"upstream": [
"CVE-2026-59870"
],
"references": [
"https://ubuntu.com/security/CVE-2026-59870",
"https://www.cve.org/CVERecord?id=CVE-2026-59870",
"https://github.com/nodeca/js-yaml/security/advisories/GHSA-724g-mxrg-4qvm"
]
},
"related_cves": [
{
"value": "CVE-2026-59870",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360582,
"published_at": "2026-07-08T16:16:00+00:00"
}