Index: branches/5.2.x/core/kernel/db/cat_event_handler.php
===================================================================
diff -u -N -r16692 -r16781
--- branches/5.2.x/core/kernel/db/cat_event_handler.php	(.../cat_event_handler.php)	(revision 16692)
+++ branches/5.2.x/core/kernel/db/cat_event_handler.php	(.../cat_event_handler.php)	(revision 16781)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: cat_event_handler.php 16692 2021-08-31 09:24:09Z alex $
+* @version	$Id: cat_event_handler.php 16781 2024-01-04 10:58:30Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -1893,18 +1893,33 @@
 		// get PerPage (forced -> session -> config -> 10)
 		$object->SetPerPage($this->getPerPage($event));
 
-		// main lists on Front-End have special get parameter for page
-		$page = $object->isMainList() ? $this->Application->GetVar('page') : false;
+		// Main lists on Front-End have special get parameter for page.
+		if ( $object->isMainList() ) {
+			$page = $this->Application->GetVarFiltered('page', false, FILTER_VALIDATE_INT);
+		}
+		else {
+			$page = false;
+		}
 
 		if ( !$page ) {
-			// page is given in "env" variable for given prefix
-			$page = $this->Application->GetVar($event->getPrefixSpecial() . '_Page');
+			// Page is given in "env" variable for given prefix.
+			$page = $this->Application->GetVarFiltered(
+				$event->getPrefixSpecial() . '_Page',
+				false,
+				FILTER_VALIDATE_INT
+			);
 		}
 
 		if ( !$page && $event->Special ) {
-			// when not part of env, then variables like "prefix.special_Page" are
-			// replaced (by PHP) with "prefix_special_Page", so check for that too
-			$page = $this->Application->GetVar($event->getPrefixSpecial(true) . '_Page');
+			/*
+			 * When not part of env, then variables like "prefix.special_Page" are
+			 * replaced (by PHP) with "prefix_special_Page", so check for that too.
+			 */
+			$page = $this->Application->GetVarFiltered(
+				$event->getPrefixSpecial(true) . '_Page',
+				false,
+				FILTER_VALIDATE_INT
+			);
 		}
 
 		if ( !$object->isMainList() ) {
@@ -1913,8 +1928,8 @@
 
 			if ( !$page ) {
 				if ( $this->Application->RewriteURLs() ) {
-					// when page not found by prefix+special, then try to search it without special at all
-					$page = $this->Application->GetVar($event->Prefix . '_Page');
+					// When page not found by prefix+special, then try to search it without special at all.
+					$page = $this->Application->GetVarFiltered($event->Prefix . '_Page', false, FILTER_VALIDATE_INT);
 
 					if ( !$page ) {
 						// page not found in request -> get from session