Improperly Controlled Modification of Dynamically-Determined Object Attributes Affecting @orpc/json-schema package, versions <1.14.9
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published24 Oct 2026
- disclosed2 Oct 2026
- creditUnknown
Introduced: 2 Oct 2026
NewCVE-2026-103036 (opens in a new tab)How to fix?
Upgrade @orpc/json-schema to version 1.14.9 or higher.
Overview
Affected versions of this package are vulnerable to Improperly Controlled Modification of Dynamically-Determined Object Attributes via JsonSchemaCoercer#coerce in coercer.ts, where attacker-controlled keys from untrusted input are processed before validation by the SmartCoercionPlugin. When coercing an object, properties are collected into a plain {}, so assigning a key such as __proto__ triggers the inherited setter rather than creating an own property, causing the returned object to inherit attacker-controlled properties through the prototype chain. A second related bug allows keys like constructor or toString to resolve to Object.prototype members when looking up schema.properties[key], causing those keys to bypass unknown-property handling and select incorrect union branches.