diff --git a/src/stratifier.c b/src/stratifier.c
index d7871dd1..d5c052d4 100644
--- a/src/stratifier.c
+++ b/src/stratifier.c
@@ -2069,6 +2069,7 @@ static int send_recv_auth(stratum_instance_t *client)
 out_fail:
 	ret = -1;
 out:
+	free(buf);
 	return ret;
 }