GHSA-xqg6-98cw-gxhq Prototype Pollution via FormData Processing in Qwik City

• npm @builder.io/qwik-city: < 1.19.0 → fixed in 1.19.0

Summary A Prototype Pollution vulnerability exists in the `formToObj()` function within `@builder.io/qwik-city` middleware. The function processes form field names with dot notation (e.g., `user.name`) to create nested objects, but fails to sanitize dangerous property names like `__proto__`, `constructor`, and `prototype`. This allows unauthenticated attackers to pollute `Object.prototype` by sending crafted HTTP POST requests, potentially leading to privilege escalation, authentication bypass, or denial of service. Impact An unauthenticated attacker can supply specially crafted form field names that cause formToObj() to write dangerous keys (for example __proto__, constructor, prototype) into parsed objects. This results in Prototype Pollution of the server process and can cause privilege escalation, auth bypass, denial-of-service, or other global application integrity failures depending on how objects are used.