CVE-2026-61534

Yayson is a JavaScript library for serializing and reading JSON:API data. Prior to 4.3.0 , Store and LegacyStore use attacker-controlled type, id, and relationship names directly as keys in plain-object lookup tables. A JSON:API document with type: "__proto__" writes onto Object.prototype, giving...

yayson: Prototype pollution in Store/LegacyStore deserialization

Summary Store/LegacyStore key internal lookup tables by the type, id, and relationship names from a JSON:API document. Because these were plain objects, a document with type: "proto" writes onto Object.prototype, polluting every object in the process. Severity Suggested CVSS v3.1...