diff --git a/library/lms.c b/library/lms.c
index 4a42f67..c647730 100644
--- a/library/lms.c
+++ b/library/lms.c
@@ -537,9 +537,8 @@
     ret = 0;
 
 exit:
-    mbedtls_platform_zeroize(tree, node_bytes *
+    mbedtls_zeroize_and_free(tree, node_bytes *
                              MERKLE_TREE_NODE_AM(ctx->params.type));
-    mbedtls_free(tree);
 
     return ret;
 }
@@ -700,9 +699,8 @@
     ret = 0;
 
 exit:
-    mbedtls_platform_zeroize(tree, node_bytes *
+    mbedtls_zeroize_and_free(tree, node_bytes *
                              MERKLE_TREE_NODE_AM(priv_ctx->params.type));
-    mbedtls_free(tree);
 
     return ret;
 }