diff --git a/src/hb-wasm-api-buffer.hh b/src/hb-wasm-api-buffer.hh
index 8feb0ee94..20e9b484c 100644
--- a/src/hb-wasm-api-buffer.hh
+++ b/src/hb-wasm-api-buffer.hh
@@ -130,6 +130,8 @@ HB_WASM_API (bool_t, buffer_copy_contents) (HB_WASM_EXEC_ENV
     return true;
   }
 
+  buffer_contents_free (exec_env, contentsptr);
+
   contents->length = length;
   contents->info = wasm_runtime_module_dup_data (module_inst, (const char *) buffer->info, length * sizeof (buffer->info[0]));
   contents->pos = wasm_runtime_module_dup_data (module_inst, (const char *) buffer->pos, length * sizeof (buffer->pos[0]));
diff --git a/src/hb-wasm-api-face.hh b/src/hb-wasm-api-face.hh
index ece557f46..2a458f6df 100644
--- a/src/hb-wasm-api-face.hh
+++ b/src/hb-wasm-api-face.hh
@@ -61,6 +61,8 @@ HB_WASM_API (bool_t, face_copy_table) (HB_WASM_EXEC_ENV
     return true;
   }
 
+  blob_free (exec_env, blobptr);
+
   blob->length = length;
   blob->data = wasm_runtime_module_dup_data (module_inst, hb_data, length);