diff --git a/storage/filesystem.go b/storage/filesystem.go
index f289ff5..f423f06 100644
--- a/storage/filesystem.go
+++ b/storage/filesystem.go
@@ -29,7 +29,7 @@ type filesystemBackend struct {
 }
 
 var (
-	validFilenameRegex  = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9@_-]+(.[a-zA-Z]+)?$`)
+	validFilenameRegex  = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9@\._-]+(.[a-zA-Z]+)?$`)
 	defaultResourceName = "default"
 )