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Fix use-after-free serializing an array grown by an element's hook #22714

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Merged
iliaal merged 1 commit into from
Jul 15, 2026
+27 −2
Merged

Fix use-after-free serializing an array grown by an element's hook #22714

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21 changes: 21 additions & 0 deletions ext/standard/tests/serialize/serialize_array_ref_reentrancy.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
--TEST--
serialize(): a by-reference __serialize() that grows the array being walked must not free it
--FILE--
<?php
class G {
public $ref;
public function __serialize(): array {
for ($i = 0; $i < 128; $i++) {
$this->ref[] = 'x' . $i;
}
return ['d' => 1];
}
}
$g = new G();
$inner = [$g, 'tail'];
$g->ref = &$inner;
$top = [&$inner];
var_dump(serialize($top));
?>
--EXPECT--
string(59) "a:1:{i:0;a:2:{i:0;O:1:"G":1:{s:1:"d";i:1;}i:1;s:4:"tail";}}"
8 changes: 6 additions & 2 deletions ext/standard/var.c
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Expand Up @@ -1303,13 +1303,17 @@ static void php_var_serialize_intern(smart_str *buf, zval *struc, php_serialize_
zend_release_properties(myht);
return;
}
case IS_ARRAY:
case IS_ARRAY: {
smart_str_appendl(buf, "a:", 2);
myht = Z_ARRVAL_P(struc);
bool rcn = !is_root && (in_rcn_array || GC_REFCOUNT(myht) > 1);
GC_TRY_ADDREF(myht);
php_var_serialize_nested_data(
buf, struc, myht, zend_array_count(myht), /* incomplete_class */ false, var_hash,
!is_root && (in_rcn_array || GC_REFCOUNT(myht) > 1));
rcn);
GC_TRY_DTOR_NO_REF(myht);
return;
}
case IS_REFERENCE:
struc = Z_REFVAL_P(struc);
goto again;
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