diff --git a/rust/src/detect/transforms/base64.rs b/rust/src/detect/transforms/base64.rs
index ee3ec1ba15..e9de8a9fe9 100644
--- a/rust/src/detect/transforms/base64.rs
+++ b/rust/src/detect/transforms/base64.rs
@@ -191,7 +191,8 @@ fn parse_transform_base64(
 
 unsafe fn base64_parse(c_arg: *const c_char) -> *mut DetectTransformFromBase64Data {
     if c_arg.is_null() {
-        return std::ptr::null_mut();
+        let detect = DetectTransformFromBase64Data::default();
+        return Box::into_raw(Box::new(detect));
     }
 
     if let Ok(arg) = CStr::from_ptr(c_arg).to_str() {