Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, a ${...} expression or backtick in a query parameter default is emitted into a module-level template literal emitted by zod schema generation without safe encoding. This permits attacker-controlled JavaScript to be evaluated when the generated zod schema module is imported, resulting in code execution in the developer, CI, test, or application environment. The affected code is packages/zod/src/index.ts function formatDefaultValue. This issue is fixed in version 8.21.0.

Affected: npm: orval

### Summary

Orval's zod schema generation emits the **query-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

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

Malicious input: a query 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 spe…