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.