`nuxt-api-party` is an open source module to proxy API requests. The library allows the user to send many options directly to `ofetch`. There is no filter on which options are available. We can abuse the retry logic to cause the server to crash from a stack overflow. fetchOptions are obtained directly from the request body. A malicious user can construct a URL known to not fetch successfully, then set the retry attempts to a high value, this will cause a stack overflow as ofetch error handling works recursively resulting in a denial of service. This issue has been addressed in version 0.22.1. Users are advised to upgrade. Users unable to upgrade should limit ofetch options.
Affected: npm: nuxt-api-party
### Summary `nuxt-api-party` allows developers to proxy requests to an API without exposing credentials to the client. [`ofetch`](https://github.com/unjs/ofetch) is used to send the requests.
The library allows the user to send many options directly to `ofetch`. There is no filter on which options are available. We can abuse the retry logic to cause the server to crash from a stack overflow.
### Details `fetchOptions` [are obtained directly from the request body](https://github.com/johannschopplich/nuxt-api-party/blob/777462e1e3af1d9f8938aa33f230cd8cb6e0cc9a/src/runtime/server/handler.ts#L27). These are then [passed directly into `ofetch` ](https://github.com/johannschopplich/nuxt-api-party/blob/777462e1e3af1d9f8938aa33f230cd8cb6e0cc9a/src/runtime/server/handler.ts#L57C15-L57C15).
We can construct a URL we know will not fetch successfully, then set the retry attempts to a high value, this will cause a stack overflow as ofetch error handling works recursively.
### PoC POC using Node.
```js await fetch("http://localhost:3000/api/__api_party/MyEndpoint", { method: "POST", body: JSON.stringify({ path: "x:x", retry: 9999999 }), headers: { "Content-Type": "application/json" } }) ```
We can use `__proto__` as a substitute for the endpoint if it is not known.
```js await fetch("http://localhost:3000/api/__api_party/__proto__", { method: "POST", body: JSON.stringify({ path: "x:x", retry: 9999999 }), headers: { "Content-Type": "application/json" } }) `…