CVE-2026-103036: medium-severity vulnerability in middleapi orpc
@orpc/json-schema: Prototype injection in smart coercion
Published · Updated
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.5epss 0.2%
exploitation probability
0.2%top 87% of all CVEs
observed exploitation
nono source reports it
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/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Affected products
middleapi · orpcRelated CVEs — middleapi orpc
In the same product, most dangerous first.
CVE-2026-28794CRITICALoRPC: Prototype Pollution in `@orpc/client` via `StandardRPCJsonSerializer` DeserializationEPSS 1.3%CVE-2026-77360MEDIUMoRPC: Vary Header Injection in CORS Plugin leading to potential Cache/CORS BypassEPSS 0.5%CVE-2026-33331HIGHoRPC: Stored XSS in OpenAPI Reference Plugin via unescaped JSON.stringifyEPSS 0.3%CVE-2026-103918MEDIUM@orpc/zod: Prototype injection in smart coercionEPSS 0.2%