I’ve gotten this as well and am unable to see it in the security advisory section of the project the email mentions. However, I was able to find this notice on the maps api documentation site. I assume this is what the advisory is for.

Security notice: We have become aware of a security issue that may be affecting websites using specific third-party libraries (including polyfill.io). This issue can sometimes redirect visitors away from the intended website without website owner knowledge or permission. Many of our JavaScript samples previously included a polyfill.io script declaration. We have removed this from our samples. If you have used our JavaScript samples that contain this declaration, we recommend removing the declaration.

I’ve gotten this as well and am unable to see it in the security advisory section of the project the email mentions. However, I was able to find this notice on the maps api documentation site. I assume this is what the advisory is for. (For reference: https://developers.google.com/maps/documentation/javascript/error-messages)

Security notice: We have become aware of a security issue that may be affecting websites using specific third-party libraries (including polyfill.io). This issue can sometimes redirect visitors away from the intended website without website owner knowledge or permission. Many of our JavaScript samples previously included a polyfill.io script declaration. We have removed this from our samples. If you have used our JavaScript samples that contain this declaration, we recommend removing the declaration.