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CVE-2026-107301

CVE-2026-107301 · msgpack5: Partial options disable prototype protection

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 6.5 · Medium · EPSS 0.4% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • msgpack5

    Versions
    • < 6.1.0: Affected

    No fix published

  • msgpack5 npm

    Affected ranges
    • SEMVER: < 6.1.0

    Update to 6.1.0

Original sources

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