diff --git a/oauth2_provider/oauth2_backends.py b/oauth2_provider/oauth2_backends.py
index 3ddb9c90b..0c43292af 100644
--- a/oauth2_provider/oauth2_backends.py
+++ b/oauth2_provider/oauth2_backends.py
@@ -1,5 +1,5 @@
 import json
-from urllib.parse import urlparse, urlunparse
+from urllib.parse import unquote, urlparse, urlunparse
 
 from oauthlib import oauth2
 from oauthlib.common import Request as OauthlibRequest
@@ -238,6 +238,22 @@ def extract_body(self, request):
         return body
 
 
+class JSONAndFormUrlencodedOAuthLibCore(JSONOAuthLibCore):
+    def extract_body(self, request):
+        # fixes base64 encoded form-submission. you can't control what all oauth clients use.
+        if request.content_type in ["application/x-www-form-urlencoded"]:
+            try:
+                query_string = request.body.decode("utf-8")
+                query_params = {p.split("=")[0]: unquote(p.split("=")[1]) for p in query_string.split("&")}
+                res = query_params.items()
+
+                return res
+            except:
+                pass
+
+        return super(JSONAndFormUrlencodedOAuthLibCore, self).extract_body(request)
+
+
 def get_oauthlib_core():
     """
     Utility function that returns an instance of