diff --git a/wapitiCore/net/crawler.py b/wapitiCore/net/crawler.py
index c83c05965..5e9e90776 100644
--- a/wapitiCore/net/crawler.py
+++ b/wapitiCore/net/crawler.py
@@ -273,7 +273,7 @@ async def async_request(
         if form.enctype and not form.is_multipart:
             form_headers = {"Content-Type": form.enctype}
 
-        if isinstance(headers, dict) and headers:
+        if isinstance(headers, (dict, httpx.Headers)) and headers:
             form_headers.update(headers)
 
         if form.referer: