diff --git a/mod/assign/feedback/editpdf/classes/pdf.php b/mod/assign/feedback/editpdf/classes/pdf.php
index c3b6921088c..e592bc382ae 100644
--- a/mod/assign/feedback/editpdf/classes/pdf.php
+++ b/mod/assign/feedback/editpdf/classes/pdf.php
@@ -632,7 +632,7 @@ class pdf extends TcpdfFpdi {
         $gsexec = \escapeshellarg($CFG->pathtogs);
         $tempdstarg = \escapeshellarg($tempdst);
         $tempsrcarg = \escapeshellarg($tempsrc);
-        $command = "$gsexec -q -sDEVICE=pdfwrite -dBATCH -dNOPAUSE -sOutputFile=$tempdstarg $tempsrcarg";
+        $command = "$gsexec -q -sDEVICE=pdfwrite -dSAFER -dBATCH -dNOPAUSE -sOutputFile=$tempdstarg $tempsrcarg";
         exec($command);
         if (!file_exists($tempdst)) {
             // Something has gone wrong in the conversion.