msgpack5: Quadratic parsing in the streaming decoder
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-107297
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 16:49 UTC · Revision 1
Source evidence
msgpack5: Quadratic parsing in the streaming decoder
core-osv · Original sourcePublished 8 Oct 2026, 17:07 UTC
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0.
osv:CVE-2026-107297
Complete source record
{
"id": "bd499cba9ebe1db4e610dbd9caf7061913a73934729cf106584afcc3c199a7e9",
"url": "https://osv.dev/vulnerability/CVE-2026-107297",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "msgpack5: Quadratic parsing in the streaming decoder",
"summary": "msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0.",
"evidence": "osv:CVE-2026-107297",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-107297",
"aliases": [
"CVE-2026-107297",
"GHSA-gcx5-hxj7-gpqq"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/mcollina/msgpack5",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "3730a5a754ec06912e42865eed9489ed64238ecb"
},
{
"fixed": "e4827641d3105e295cbbd56e9c5389978547eab4"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "6.1.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "e4827641d3105e295cbbd56e9c5389978547eab4"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "3730a5a754ec06912e42865eed9489ed64238ecb"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v6.1.0"
}
]
}
}
],
"versions": [
"v6.0.2",
"v6.0.0",
"v5.3.2",
"v5.3.1",
"v3.6.1",
"v3.6.0",
"v5.3.0",
"v5.2.1",
"v5.2.0",
"v5.1.0",
"v5.0.0",
"v4.4.0",
"v4.3.0",
"v4.2.0",
"v4.1.0",
"v4.0.2",
"v4.0.1",
"v4.0.0",
"v3.5.0",
"v3.4.1",
"v3.4.0",
"v3.3.0",
"v3.2.0",
"v3.1.0",
"v3.0.0",
"v2.3.1",
"v2.3.0",
"v2.2.0",
"v2.1.0",
"v2.0.0",
"v1.6.0",
"v1.5.0",
"v1.3.2",
"v1.3.1",
"v1.2.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-107297.json"
}
}
],
"modified": "2026-10-28T02:30:30.700604535Z",
"provider": "osv",
"references": [
"https://github.com/mcollina/msgpack5/releases/tag/v6.1.0",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107297.json",
"https://github.com/mcollina/msgpack5/security/advisories/GHSA-gcx5-hxj7-gpqq",
"https://nvd.nist.gov/vuln/detail/CVE-2026-107297",
"https://github.com/mcollina/msgpack5/commit/e4827641d3105e295cbbd56e9c5389978547eab4"
],
"provider_metadata": {
"cwe_ids": [
"CWE-407"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107297.json"
}
},
"related_cves": [
{
"value": "CVE-2026-107297",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 497602,
"published_at": "2026-10-08T17:07:03.74+00:00"
}