Use PyOS_snprintf instead of sprintf.
diff --git a/Python/dynload_dl.c b/Python/dynload_dl.c
index 5a62d6f..4675a67 100644
--- a/Python/dynload_dl.c
+++ b/Python/dynload_dl.c
@@ -21,6 +21,6 @@
 {
 	char funcname[258];
 
-	sprintf(funcname, "init%.200s", shortname);
+	PyOS_snprintf(funcname, sizeof(funcname), "init%.200s", shortname);
 	return dl_loadmod(Py_GetProgramName(), pathname, funcname);
 }