Yayson is a library for serializing and reading JSON API data in JavaScript. Prior to 4.3.0, Store and LegacyStore use attacker-controlled JSON:API type, id, and relationship names as keys in plain-object lookup tables in src/yayson/store.ts and src/yayson/legacy-store.ts. A document whose type is __proto__ causes model-cache writes to modify Object.prototype, with the attacker controlling the polluted property name through id and its value through attributes. The malicious type can also be supplied by an included resource, and LegacyStore is reachable when a configured types mapping resolves to __proto__. Unsafe relationship names including __proto__, constructor, and prototype provide additional document-derived member paths. The resulting process-wide prototype pollution can cause denial of service and logic corruption; authorization bypass or code execution depends on suitable gadgets in the consuming application. This issue is fixed in version 4.3.0.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-325j-mg25-8q58 | yayson: Prototype pollution in Store/LegacyStore deserialization |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Mon, 14 Sep 2026 21:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Yayson is a library for serializing and reading JSON API data in JavaScript. Prior to 4.3.0, Store and LegacyStore use attacker-controlled JSON:API type, id, and relationship names as keys in plain-object lookup tables in src/yayson/store.ts and src/yayson/legacy-store.ts. A document whose type is __proto__ causes model-cache writes to modify Object.prototype, with the attacker controlling the polluted property name through id and its value through attributes. The malicious type can also be supplied by an included resource, and LegacyStore is reachable when a configured types mapping resolves to __proto__. Unsafe relationship names including __proto__, constructor, and prototype provide additional document-derived member paths. The resulting process-wide prototype pollution can cause denial of service and logic corruption; authorization bypass or code execution depends on suitable gadgets in the consuming application. This issue is fixed in version 4.3.0. | |
| Title | Yayson: Prototype pollution in the Store/LegacyStore deserialization | |
| Weaknesses | CWE-1321 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-09-14T19:19:45.499Z
Reserved: 2026-07-10T16:27:03.093Z
Link: CVE-2026-61534
Updated: 2026-09-14T19:19:10.572Z
Status : Received
Published: 2026-09-14T16:17:16.847
Modified: 2026-09-14T20:16:48.813
Link: CVE-2026-61534
No data.
OpenCVE Enrichment
No data.
Weaknesses
Github GHSA