ubuntu-cve-2026-73643
Vulnerability from osv_ubuntu
Published
2026-08-13 18:18
Modified
2026-08-19 11:11
Summary
Details
js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a flow-sequence entry is recognized as a key: value pair. If the key is a nested flow sequence of the same shape, every level is parsed twice, causing O(2^n) work and allowing an input under 200 bytes to keep one CPU busy for minutes, block the Node.js event loop, and stall the process. No anchors, aliases, merges, tags, or nondefault options are required. This issue is fixed in version 5.2.2.
Severity
7.5 (High)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "3.10.0+dfsg-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml@3.10.0+dfsg-1?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.9.1+dfsg-1",
"3.10.0+dfsg-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "3.13.1+dfsg-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml@3.13.1+dfsg-2?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.13.1+dfsg-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "4.1.0+dfsg+~4.0.5-6"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml@4.1.0+dfsg+~4.0.5-6?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"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"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "4.1.0+dfsg+~4.0.5-7"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml@4.1.0+dfsg+~4.0.5-7?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.1.0+dfsg+~4.0.5-7"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "node-js-yaml",
"binary_version": "4.1.1+dfsg+~4.0.9-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "node-js-yaml",
"purl": "pkg:deb/ubuntu/node-js-yaml@4.1.1+dfsg+~4.0.9-1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.1.0+dfsg+~4.0.5-7",
"4.1.1+dfsg+~4.0.9-1"
]
}
],
"aliases": [],
"details": "js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 until 5.2.2, parsing a small YAML document can take exponential time when an application calls load() or loadAll() on untrusted input. In src/parser/parser.ts, readFlowCollection uses restoreState and calls parseNode a second time when a flow-sequence entry is recognized as a key: value pair. If the key is a nested flow sequence of the same shape, every level is parsed twice, causing O(2^n) work and allowing an input under 200 bytes to keep one CPU busy for minutes, block the Node.js event loop, and stall the process. No anchors, aliases, merges, tags, or nondefault options are required. This issue is fixed in version 5.2.2.",
"id": "UBUNTU-CVE-2026-73643",
"modified": "2026-08-19T11:11:14Z",
"published": "2026-08-13T18:18:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-73643"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-73643"
},
{
"type": "REPORT",
"url": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-pm4m-ph32-ghv5"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-73643"
]
}
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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