Orval: Import-time RCE via header-parameter default -> zod module-level template literal

Summary

Orval's zod schema generation emits the header-parameter default value as a module-level template literal (export const Default = <default>;) without escaping ${ or the backtick. A default of the form v${<code>}w injects a live JavaScript expression evaluated when the generated zod schema module is imported, executing attacker-controlled code at import — no request or function call needed. Verified on Orval 8.19.0; survives default OpenAPI validation.

Details

export const …Default = `v${globalThis.ORVPWN()}w`;   // ${...} = arbitrary JS expression, runs at import

Malicious input: a header parameter with a default of v${<attacker JS>}w. ${...} permits any JS expression.

Note: this is one of several default-bearing positions that reach the same unescaped zod template-literal sink; a single fix (escape default values) closes all of them, and a CNA may choose to consolidate the related reports.

PoC

reproduce.sh (+ make_spec.py) attached: generates the zod schema with default validation, bundles it, imports it, and shows a marker written at import. Verified on 8.19.0.

Impact

Code execution at import in any application that imports a zod schema module generated from an attacker-controlled or attacker-influenced OpenAPI description.

Suggested fix

Emit default values via a proper string-literal encoder (JSON.stringify, or escape backtick and ${ if a template literal must be used); never interpolate a spec value into a template literal. Apply to every default position. make_spec.py reproduce.sh