diff --git a/ext/random/engine_mt19937.c b/ext/random/engine_mt19937.c
index a84fb9585c80..a1fba4b8367c 100644
--- a/ext/random/engine_mt19937.c
+++ b/ext/random/engine_mt19937.c
@@ -348,30 +348,30 @@ PHP_METHOD(Random_Engine_Mt19937, __unserialize)
 
 	/* Verify the expected number of elements, this implicitly ensures that no additional elements are present. */
 	if (zend_hash_num_elements(d) != 2) {
-		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(engine->std.ce->name));
+		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %pS object", engine->std.ce->name);
 		RETURN_THROWS();
 	}
 
 	/* members */
 	t = zend_hash_index_find(d, 0);
 	if (!t || Z_TYPE_P(t) != IS_ARRAY) {
-		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(engine->std.ce->name));
+		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %pS object", engine->std.ce->name);
 		RETURN_THROWS();
 	}
 	object_properties_load(&engine->std, Z_ARRVAL_P(t));
 	if (EG(exception)) {
-		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(engine->std.ce->name));
+		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %pS object", engine->std.ce->name);
 		RETURN_THROWS();
 	}
 
 	/* state */
 	t = zend_hash_index_find(d, 1);
 	if (!t || Z_TYPE_P(t) != IS_ARRAY) {
-		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(engine->std.ce->name));
+		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %pS object", engine->std.ce->name);
 		RETURN_THROWS();
 	}
 	if (!engine->engine.algo->unserialize(engine->engine.state, Z_ARRVAL_P(t))) {
-		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %s object", ZSTR_VAL(engine->std.ce->name));
+		zend_throw_exception_ex(NULL, 0, "Invalid serialization data for %pS object", engine->std.ce->name);
 		RETURN_THROWS();
 	}
 }