As part of WordPress 6.2,
wpdb::prepare() has been updated to escape Identifiers (such as Table and Field names) with the
%i placeholder (#52506).
This ensures these values are escaped correctly and don’t lead to SQL Injection Vulnerabilities.
$table = 'my_table';
$field = 'my_field';
$value = 'my_value';
$wpdb->prepare('SELECT * FROM %i WHERE %i = %s', $table, $field, $value);
// SELECT * FROM `my_table` WHERE `my_field` = 'my_value'
While this protects you against SQL Injection, where possible you should limit the values the user (attacker) can choose via an allow-list of trusted values; e.g.
$fields = array(
'name' => 'user_nicename',
'url' => 'user_url',
'created' => 'DATE(created)',
$sql .= ' ORDER BY ' . ($fields[$order_field] ?? 'user_login');
The change to add support for %i has a small performance improvement, as there is a little bit less Regular Expression work involved (generally the more parameters, the better the improvement).
In the Future
This was going to be released in WordPress 6.1, but a problem was identified in RC5 where the use of
'%%%s%%' (which can often be seen in
LIKE queries) stopped working. For reference, the documentation says “numbered or formatted string placeholders” will not have quotes added by this function (an old/unsafe feature), but this also happens when a placeholder immediately follows a “%”.
WordPress is looking to use %i in core Core is the set of software required to run WordPress. The Core Development Team builds WordPress. (#56091).
This change will help developers use the
literal-string type for the
$query parameter (this is where the
$query is written as a developer-defined string, and all user values are provided separately).
Props to @davidbaumwald for reviewing this dev note Each important change in WordPress Core is documented in a developers note, (usually called dev note). Good dev notes generally include a description of the change, the decision that led to this change, and a description of how developers are supposed to work with that change. Dev notes are published on Make/Core blog during the beta phase of WordPress release cycle. Publishing dev notes is particularly important when plugin/theme authors and WordPress developers need to be aware of those changes.In general, all dev notes are compiled into a Field Guide at the beginning of the release candidate phase..
#6-1, #dev-notes, #dev-notes-6-1, #performance, #wpdb