I have a problem with an missing HTTP referrer header on Safari iOS 14.6+ in a link click request from inside an iframe. Outside the iframe it works fine. The referrer is not empty and contains the domain of the current site.
I tried already to set a Referrer-Policy on the HTTP response header also as a HTTP meta tag on the main page with different settings. Nothing helps.
The reason might be the cross site tracking prevention but at least webkit should send the domain as the value of referrer header.
The iframe is loaded from a Google Ad Manager tag and I have no chance to do javascript Kung-Fu inside the iframe.
There is no src attribute on the iframe and it begins as follows:
<iframe id="google_ads_iframe_/foo" title="3rd party ad content" name="google_ads_iframe_/foo" width="300" height="250" scrolling="no" marginwidth="0" marginheight="0" frameborder="0" data-load-complete="true" data-google-container-id="2" style="border: 0px; vertical-align: bottom;">
What else could I do to send the referrer header with the request after click on the link inside the iframe?