diff --git a/lib/easy.c b/lib/easy.c
index bed94a4444..ef023aa92b 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -981,6 +981,10 @@ void curl_easy_reset(struct Curl_easy *data)
 
   data->progress.flags |= PGRS_HIDE;
   data->state.current_speed = -1; /* init to negative == impossible */
+
+  /* zero out authentication data: */
+  memset(&data->state.authhost, 0, sizeof(struct auth));
+  memset(&data->state.authproxy, 0, sizeof(struct auth));
 }
 
 /*