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.

Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-gcx5-hxj7-gpqq msgpack5: Quadratic parsing in the streaming decoder
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 08 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 08 Oct 2026 17:15:00 +0000

Type Values Removed Values Added
Description 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.
Title msgpack5: Quadratic parsing in the streaming decoder
Weaknesses CWE-407
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-08T17:26:27.457Z

Reserved: 2026-10-07T15:53:23.587Z

Link: CVE-2026-107297

cve-icon Vulnrichment

Updated: 2026-10-08T17:26:23.378Z

cve-icon NVD

Status : Received

Published: 2026-10-08T17:17:15.550

Modified: 2026-10-08T18:17:17.490

Link: CVE-2026-107297

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-08T19:00:07Z

Weaknesses