CVE-2026-107303: high-severity vulnerability in jhipster generator-jhipster

JHipster is a development platform to quickly generate, develop, and deploy modern web applications and microservice architectures. Prior to generator-jhipster 9.4.0 and react-jhipster 1.1.0, generated applications can persist attacker-controlled Blob data and companion ContentType values, return them through generated REST endpoints, and pass them to the generated openFile helper in generators/client/generators/common/templates/src/main/webapp/app/shared/jhipster/data-utils.ts.ejs. The helper uses the returned ContentType as the browser Blob MIME type and opens an object URL, so a normal authenticated user with write access to a Blob-bearing entity can store active HTML or SVG content that may execute under the application origin when a privileged user opens it. Exploitability depends on the generated application's content security policy and target-browser Blob behavior. This issue is fixed in generator-jhipster 9.4.0 and react-jhipster 1.1.0.