CVE-2026-107297

msgpack5: Quadratic parsing in the streaming decoder

Published Oct 8, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-gcx5-hxj7-gpqq msgpack5: Quadratic parsing in the streaming decoder
History
Type Values Removed Values Added
First Time appeared Mcollina
Mcollina msgpack5
Vendors & Products Mcollina
Mcollina msgpack5
Type Values Removed Values Added
Metrics ssvc

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 8, 2026, 5:26 PM
Reserved
Oct 7, 2026, 3:53 PM
Status
Deferred
Published
Oct 8, 2026, 5:17 PM
Modified
Oct 8, 2026, 8:48 PM