middleapi orpc up to 1.14.8 SmartCoercionPlugin prototype pollution

Summaryinfo

A vulnerability labeled as critical has been found in middleapi orpc up to 1.14.8. Impacted is an unknown function of the component SmartCoercionPlugin. The manipulation results in prototype pollution. This vulnerability is known as CVE-2026-103036. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in middleapi orpc up to 1.14.8. Affected is an unknown part of the component SmartCoercionPlugin. The manipulation with an unknown input leads to a prototype pollution vulnerability. CWE is classifying the issue as CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-103036 since 09/29/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 1.14.9 eliminates this vulnerability.

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Productinfo

Vendor

• middleapi

Name

• orpc

Version

• 1.14.0
• 1.14.1
• 1.14.2
• 1.14.3
• 1.14.4
• 1.14.5
• 1.14.6
• 1.14.7
• 1.14.8

Website

• Product: https://github.com/middleapi/orpc/

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