title: S3 CORS, always send Vary: Origin
body: <p>I am using an S3 bucket behind Cloudfront with CORS enabled. If the client makes a request with the Origin header, then S3 (and cloudfront) respond with a "Vary: Origin" header, however if the request is made without the Origin, header then the response does not contain any Vary Header.</p>
  
  <p>This is problematic because I use a resource from cloudfront/s3 in an img tag, in which case the browser makes the request without the Origin header, and then later make an ajax request for said image. The browser then uses the cached version of the image, without the Access-Control-Allow-Origin header, and therefore denies the request.</p>
  
  <p>Is there any way to get S3 to always return the "Vary: Origin" header?</p>