Is this a bug report?

Yes

Have you read the Contributing Guidelines?

Yes

Steps to Reproduce

1. Add a WebView to your ReactNative app.
2. Browse to a website that sets cookies with illegal characters, like ò.
3. Try to do a backend call to that same domain using fetch

Expected Behavior

The app should never crash on values that are set by a website.

Actual Behavior

The app crashes when illegal cookies are set.

I'm working on a PR, I'd like to use this issue to keep track / discuss.