GHSA-49r3-2549-3633

### Impact

This vulnerability impacts applications using the [omniauth-apple](https://github.com/nhosoya/omniauth-apple) strategy of OmniAuth and using the `info.email` field of OmniAuth's [Auth Hash Schema](https://github.com/omniauth/omniauth/wiki/Auth-Hash-Schema) for any kind of identification. The value of this field may be set to any value of the attacker's choice including email addresses of other users.

For example, an application using omniauth-apple with the following code will be impacted: ```ruby def omniauth_callback auth_hash = request.env['omniauth.auth'] @authenticated_user = User.find_by(email: auth_hash.info.email) end ```

Applications not using `info.email` for identification but are instead using the `uid` field are not impacted in the same manner. Note, these applications may still be negatively affected if the value of `info.email` is being used for other purposes.

### Patches

Applications using affected versions of omniauth-apple are advised to upgrade to omniauth-apple version 1.0.1 or later.

### Workarounds

If unable to upgrade to a patched version, monkey patching `OmniAuth::Strategies::Apple#email` as follows is advised as a workaround:

```ruby module OmniAuth module Strategies class Apple def email id_info['email'] end end end end ```