diff --git a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-addbybiblionumber.tt b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-addbybiblionumber.tt
index fe6b54c9d7..7786a1097f 100644
--- a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-addbybiblionumber.tt
+++ b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-addbybiblionumber.tt
@@ -48,7 +48,7 @@
                                             [% FOREACH biblio IN biblios %]
                                                 <input type="hidden" name="biblionumber" value="[% biblio.biblionumber | html %]" />
                                             [% END %]
-                                            <input type="hidden" name="modifyshelfcontents" value="1" />
+                                            <input type="hidden" name="op" value="cud-modifyshelfcontents" />
                                         </fieldset>
                                         <fieldset class="action">
                                             <input type="submit" value="Save" class="btn btn-primary" />
@@ -64,7 +64,7 @@
                                                 <input type="hidden" name="biblionumber" value="[% biblio.biblionumber | html %]">
                                             [% END %]
                                             <input type="hidden" name="shelfnumber" value="[% shelfnumber | html %]" />
-                                            <input type="hidden" name="modifyshelfcontents" value="1" /></fieldset>
+                                            <input type="hidden" name="op" value="cud-modifyshelfcontents" /></fieldset>
                                             <fieldset class="action">
                                                 <input type="submit" value="Save" class="btn btn-primary" />
                                                 <a class="close cancel" href="#">Cancel</a>
@@ -93,6 +93,7 @@
                                         <input type="hidden" name="biblionumber" value="[% biblio.biblionumber | html %]" />
                                     [% END %]
                                     <fieldset class="action">
+                                        <input type="hidden" name="op" value="cud-add" />
                                         <input type="hidden" name="sortfield" value="title" />
                                         <input type="submit" value="Save" class="btn btn-primary" />
                                         <a class="close cancel" href="#">Cancel</a>
diff --git a/opac/opac-addbybiblionumber.pl b/opac/opac-addbybiblionumber.pl
index fc31627882..1916c26e9e 100755
--- a/opac/opac-addbybiblionumber.pl
+++ b/opac/opac-addbybiblionumber.pl
@@ -28,6 +28,7 @@ use Koha::Biblios;
 use Koha::Virtualshelves;
 
 my $query           = CGI->new;
+my $op              = $query->param('op') // q{};
 my @biblionumbers   = $query->multi_param('biblionumber');
 my $selectedshelf   = $query->param('selectedshelf');
 my $newshelf        = $query->param('newshelf');
@@ -54,7 +55,9 @@ my ( $template, $loggedinuser, $cookie ) = get_template_and_user(
     }
 );
 
-if ($newvirtualshelf) {
+if( $op && $op !~ /^cud-/ ) {
+    $authorized = 0;
+} elsif ($newvirtualshelf) {
     if ($loggedinuser > 0
         and (  !$public
             or $public and $loggedinuser > 0 && C4::Context->preference('OpacAllowPublicListCreation') )