CVE-2026-107301Medium· 6.5▾ Sunlitmsgpack5 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__…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 35.8 · likelihood 0 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
msgpack5 < 6.1.0Patched in:
msgpack5 6.1.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-107302High· 7.5msgpack5 is a msgpack v5 implementation for node.js and the browser
CVE-2026-107300High· 7.5msgpack5 is a msgpack v5 implementation for node.js and the browser
CVE-2026-107297Medium· 5.9msgpack5 is a msgpack v5 implementation for node.js and the browser
CVE-2026-107298Medium· 5.3msgpack5 is a msgpack v5 implementation for node.js and the browser
CVE-2026-107299Medium· 5.9msgpack5 is a msgpack v5 implementation for node.js and the browser
CVE-2026-107296Low· 3.7msgpack5 is a msgpack v5 implementation for node.js and the browser