Detections
Analytics
CVE-2026-107301
medium
Description
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, constructing msgpack5 with an empty or partial options object disables the default protoAction: 'error' protection. A decoded map containing a __proto__ key can then replace the decoded object's prototype, potentially changing inherited properties or downstream behavior, although Object.prototype is not modified globally. This issue is fixed in version 6.1.0.
References
https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m
https://github.com/mcollina/msgpack5/releases/tag/v6.1.0
https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774