diff --git a/phpBB/posting.php b/phpBB/posting.php
index 4f099d97ac..a82854c3a4 100644
--- a/phpBB/posting.php
+++ b/phpBB/posting.php
@@ -1242,7 +1242,7 @@ generate_forum_nav($post_data);
 // Build Forum Rules
 generate_forum_rules($post_data);
 
-if ($config['enable_post_confirm'] && !$user->data['is_registered'] && $captcha->is_solved() === false && ($mode == 'post' || $mode == 'reply' || $mode == 'quote'))
+if ($config['enable_post_confirm'] && !$user->data['is_registered'] && (isset($captcha) && $captcha->is_solved() === false) && ($mode == 'post' || $mode == 'reply' || $mode == 'quote'))
 {
 	$captcha->reset();