diff --git a/src/eap_server/tncs.c b/src/eap_server/tncs.c
index 21d83b3bd..497b51a0f 100644
--- a/src/eap_server/tncs.c
+++ b/src/eap_server/tncs.c
@@ -1231,6 +1231,7 @@ void tncs_global_deinit(void)
 	}
 
 	os_free(tncs_global_data);
+	tncs_global_data = NULL;
 }