swagger-typescript-api generates API clients for Fetch or Axios from OpenAPI specifications. Prior to 13.12.2, src/code-gen-process.ts createApiConfig copies servers[0].url into apiConfig.baseUrl, and templates/base/http-clients/fetch-http-client.ejs interpolates apiConfig.baseUrl into the generated HttpClient baseUrl field without escaping, allowing an attacker-controlled OpenAPI spec to inject TypeScript static field code that executes when the generated fetch client module is imported. This issue is fixed in version 13.12.2.

Affected: npm: swagger-typescript-api

### Summary

`swagger-typescript-api` interpolates `servers[0].url` directly into a TypeScript class-body field initializer of the generated **fetch** `HttpClient` (`templates/base/http-clients/fetch-http-client.ejs:75`), without any escaping. A malicious URL containing a `"` closes the string literal that initializes `public baseUrl` and exposes the surrounding *class body* to injection. The most direct exploit declares a new `static` field whose initializer is an async IIFE — TypeScript evaluates static field initializers at **class definition time**, which is at module load. A consumer who imports the generated client (or anything that transitively imports it) executes the injected code with no further interaction — no instantiation, no method call, no use of the baseUrl. The attacker controls the OpenAPI spec; the victim is whoever runs the generator and imports the result.

This is the highest-impact sink in the package: the trigger requires only a bare `import` of the generated module.

### Details

`createApiConfig` in `src/code-gen-process.ts:591` sets the templated `baseUrl` from the spec without sanitization:

```ts return { ... baseUrl: serverUrl, // <-- serverUrl = swaggerSchema.servers[0].url, raw ... }; ```

The fetch http-client template (`templates/base/http-clients/fetch-http-client.ejs:75`) then interpolates that value into a TS string literal that initializes a public class-body field of the generated `HttpClient`:

```ejs export class HttpClient…