Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation, and client-server communication. Prior to version 1.4.27, an Elysia cookie can be overridden by prototype pollution , eg. `__proto__`. This issue is patched in 1.4.27. As a workaround, use t.Cookie validation to enforce validation value and/or prevent iterable over cookie if possible.

Affected: npm: elysia

### Impact Elysia cookie can be overridden by prototype pollution , eg. `__proto__`

Sending cookie with the follows name can override cookie value: ```bash __proto__=%7B%22injected%22%3A%22polluted%22%7D ```

### Patches Patched by 1.4.27

### Workarounds 1. Use t.Cookie validation to enforce validation value 2. Prevent iterable over cookie if possible