CVE-2026-103036
A remote client that can reach a procedure with an object input schema can supply __proto__ to replace the prototype of the single coerced request object, or supply Object.prototype member names such as constructor and toString so inherited values are…
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
oRPC is a tool that helps build APIs that are end-to-end type-safe and adhere to OpenAPI standards. Prior to 1.14.9, the @orpc/json-schema SmartCoercionPlugin uses JsonSchemaCoercer to collect object properties in a plain object and to resolve schema.properties entries through the prototype chain. A remote client that can reach a procedure with an object input schema can supply __proto__ to replace the prototype of the single coerced request object, or supply Object.prototype member names such as constructor and toString so inherited values are treated as sub-schemas and pass the coercer's satisfaction check. Attacker-controlled inherited properties can consequently affect handler, Object.assign, or configuration lookups, while legitimate __proto__ properties are dropped. The global Object.prototype, unrelated objects, other requests, and other users are not modified, and downstream schema validation still runs. This issue is fixed in version 1.14.9.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS
- 0.23% probability · 14th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-915, CWE-1321
- Source
- security-advisories@github.com
EPSS moved from 0.2% on 3 October 2026 to 0.2% on 26 October 2026.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.