diff --git a/lib/http/middleware.go b/lib/http/middleware.go
index 8e58c6bbb..a9ccf4e2e 100644
--- a/lib/http/middleware.go
+++ b/lib/http/middleware.go
@@ -189,7 +189,7 @@ func MiddlewareCORS(allowOrigin string) Middleware {
 
 			if allowOrigin != "" {
 				w.Header().Add("Access-Control-Allow-Origin", allowOrigin)
-				w.Header().Add("Access-Control-Allow-Headers", "Authorization, Content-Type, Depth, Destination, If, Lock-Token, Overwrite, TimeOut, Translate")
+				w.Header().Add("Access-Control-Allow-Headers", "Authorization, Content-Type, Depth, Destination, If, Lock-Token, Overwrite, Prefer, TimeOut, Translate")
 				w.Header().Add("Access-Control-Allow-Methods", "COPY, DELETE, GET, HEAD, LOCK, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PROPPATCH, PUT, TRACE, UNLOCK")
 				w.Header().Add("Access-Control-Max-Age", "86400")
 			}