diff --git a/htdocs/accountancy/admin/card.php b/htdocs/accountancy/admin/card.php
index ddfe57d4c5c..79a8a531ec9 100644
--- a/htdocs/accountancy/admin/card.php
+++ b/htdocs/accountancy/admin/card.php
@@ -37,7 +37,7 @@ $langs->load("accountancy");
 
 $mesg = '';
 $action = GETPOST('action','aZ09');
-$backtopage = GETPOST('backtopage');
+$backtopage = GETPOST('backtopage','alpha');
 $id = GETPOST('id', 'int');
 $rowid = GETPOST('rowid', 'int');
 $cancel = GETPOST('cancel','alpha');
diff --git a/htdocs/compta/bank/ligne.php b/htdocs/compta/bank/ligne.php
index c5af6ef7ef7..c88220192ab 100644
--- a/htdocs/compta/bank/ligne.php
+++ b/htdocs/compta/bank/ligne.php
@@ -48,7 +48,7 @@ $action=GETPOST('action','alpha');
 $confirm=GETPOST('confirm','alpha');
 $rowid=GETPOST("rowid",'int');
 $orig_account=GETPOST("orig_account");
-$backtopage=GETPOST('backtopage');
+$backtopage=GETPOST('backtopage','alpha');
 $cancel=GETPOST('cancel','alpha');
 
 // Security check
diff --git a/htdocs/livraison/card.php b/htdocs/livraison/card.php
index 02b126306f2..81237d39782 100644
--- a/htdocs/livraison/card.php
+++ b/htdocs/livraison/card.php
@@ -54,7 +54,7 @@ if (!empty($conf->incoterm->enabled)) $langs->load('incoterm');
 
 $action=GETPOST('action', 'alpha');
 $confirm=GETPOST('confirm', 'alpha');
-$backtopage=GETPOST('backtopage');
+$backtopage=GETPOST('backtopage','alpha');
 
 // Security check
 $id = GETPOST('id', 'int');
diff --git a/htdocs/margin/checkMargins.php b/htdocs/margin/checkMargins.php
index aa494a9ad0c..9b043766c78 100644
--- a/htdocs/margin/checkMargins.php
+++ b/htdocs/margin/checkMargins.php
@@ -38,7 +38,7 @@ $action     = GETPOST('action','alpha');
 $massaction = GETPOST('massaction','alpha');
 $toselect   = GETPOST('toselect', 'array');
 $contextpage= GETPOST('contextpage','aZ')?GETPOST('contextpage','aZ'):'margindetail';   // To manage different context of search
-$backtopage = GETPOST('backtopage');
+$backtopage = GETPOST('backtopage','alpha');
 $optioncss  = GETPOST('optioncss','alpha');
 
 // Load variable for pagination
diff --git a/htdocs/opensurvey/results.php b/htdocs/opensurvey/results.php
index 9bfb15b2c24..2ce78a2f8c7 100644
--- a/htdocs/opensurvey/results.php
+++ b/htdocs/opensurvey/results.php
@@ -520,7 +520,7 @@ if (GETPOST('ajoutsujet'))
 	if (!$user->rights->opensurvey->write) accessforbidden();
 
 	print '<form name="formulaire" action="" method="POST">'."\n";
-	print '<input type="hidden" name="backtopage" value="'.GETPOST('backtopage').'">';
+	print '<input type="hidden" name="backtopage" value="'.GETPOST('backtopage','alpha').'">';
 
 	print '<div class="center">'."\n";
 	print "<br><br>"."\n";
diff --git a/htdocs/product/inventory/list.php b/htdocs/product/inventory/list.php
index cf6d8a0f359..6f443324f6b 100644
--- a/htdocs/product/inventory/list.php
+++ b/htdocs/product/inventory/list.php
@@ -69,7 +69,7 @@ $toselect   = GETPOST('toselect', 'array');
 $contextpage= GETPOST('contextpage','aZ')?GETPOST('contextpage','aZ'):'inventorylist';   // To manage different context of search
 
 $id			= GETPOST('id','int');
-$backtopage = GETPOST('backtopage');
+$backtopage = GETPOST('backtopage','alpha');
 $optioncss  = GETPOST('optioncss','alpha');
 
 // Load variable for pagination
diff --git a/htdocs/product/stock/card.php b/htdocs/product/stock/card.php
index b2a2f102ade..c95e805c3f5 100644
--- a/htdocs/product/stock/card.php
+++ b/htdocs/product/stock/card.php
@@ -48,7 +48,7 @@ $id = GETPOST("id",'int');
 if (! $sortfield) $sortfield="p.ref";
 if (! $sortorder) $sortorder="DESC";
 
-$backtopage=GETPOST("backtopage");
+$backtopage=GETPOST('backtopage','alpha');
 
 // Security check
 $result=restrictedArea($user,'stock');
diff --git a/htdocs/product/stock/product.php b/htdocs/product/stock/product.php
index 96395ab6874..01df409361c 100644
--- a/htdocs/product/stock/product.php
+++ b/htdocs/product/stock/product.php
@@ -51,7 +51,7 @@ $langs->load("stocks");
 $langs->load("sendings");
 if (! empty($conf->productbatch->enabled)) $langs->load("productbatch");
 
-$backtopage=GETPOST('backtopage');
+$backtopage=GETPOST('backtopage','alpha');
 $action=GETPOST('action','aZ09');
 $cancel=GETPOST('cancel','alpha');
 
diff --git a/htdocs/product/stock/productlot_card.php b/htdocs/product/stock/productlot_card.php
index e4dcfde07c4..70d907ae5e9 100644
--- a/htdocs/product/stock/productlot_card.php
+++ b/htdocs/product/stock/productlot_card.php
@@ -45,7 +45,7 @@ $langs->load("productbatch");
 // Get parameters
 $id			= GETPOST('id','int');
 $action		= GETPOST('action','alpha');
-$backtopage = GETPOST('backtopage');
+$backtopage = GETPOST('backtopage','alpha');
 $batch  	= GETPOST('batch','alpha');
 $productid  = GETPOST('productid','int');
 $ref        = GETPOST('ref','alpha');       // ref is productid_batch
diff --git a/htdocs/product/stock/productlot_list.php b/htdocs/product/stock/productlot_list.php
index 37b66f5c7f3..567d60911ae 100644
--- a/htdocs/product/stock/productlot_list.php
+++ b/htdocs/product/stock/productlot_list.php
@@ -45,7 +45,7 @@ $langs->load("users");
 // Get parameters
 $id			= GETPOST('id','int');
 $action		= GETPOST('action','alpha');
-$backtopage = GETPOST('backtopage');
+$backtopage = GETPOST('backtopage','alpha');
 $myparam	= GETPOST('myparam','alpha');