Disclosure 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.
Source-reported weakness categories
CWE-407
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2026-107297
Open original source · Updated Oct 08, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
GitHub Reviewed Security Advisories · GHSA-gcx5-hxj7-gpqq
Open original source · Updated Oct 08, 2026
msgpack5: Quadratic parsing in the streaming decoder
Source severity: MEDIUM / 0
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| npm | msgpack5 | < 6.1.0 | 6.1.0 |
Original records & references
PUBLISHED 2026-10-08T13:17:15-04:00
MODIFIED 2026-10-08T16:48:36-04:00
INGESTED 2026-10-10T20:55:03-04:00