diff --git a/grade/report/grader/index.php b/grade/report/grader/index.php
index 822a75842ce..f15efe25979 100644
--- a/grade/report/grader/index.php
+++ b/grade/report/grader/index.php
@@ -40,8 +40,8 @@ $target        = optional_param('target', 0, PARAM_ALPHANUM);
 $toggle        = optional_param('toggle', null, PARAM_INT);
 $toggle_type   = optional_param('toggle_type', 0, PARAM_ALPHANUM);
 
-$graderreportsifirst  = optional_param('sifirst', null, PARAM_ALPHA);
-$graderreportsilast   = optional_param('silast', null, PARAM_ALPHA);
+$graderreportsifirst  = optional_param('sifirst', null, PARAM_NOTAGS);
+$graderreportsilast   = optional_param('silast', null, PARAM_NOTAGS);
 
 // The report object is recreated each time, save search information to SESSION object for future use.
 if (isset($graderreportsifirst)) {
diff --git a/report/completion/index.php b/report/completion/index.php
index 51ddda7ea9e..5f84c266952 100644
--- a/report/completion/index.php
+++ b/report/completion/index.php
@@ -62,8 +62,8 @@ if ($csv) {
 
 // Paging
 $start   = optional_param('start', 0, PARAM_INT);
-$sifirst = optional_param('sifirst', 'all', PARAM_ALPHA);
-$silast  = optional_param('silast', 'all', PARAM_ALPHA);
+$sifirst = optional_param('sifirst', 'all', PARAM_NOTAGS);
+$silast  = optional_param('silast', 'all', PARAM_NOTAGS);
 
 // Whether to show extra user identity information
 $extrafields = get_extra_user_fields($context);
diff --git a/report/progress/index.php b/report/progress/index.php
index 69d1058261a..8f87baa8431 100644
--- a/report/progress/index.php
+++ b/report/progress/index.php
@@ -47,8 +47,8 @@ $csv = $format == 'csv' || $excel;
 
 // Paging
 $start   = optional_param('start', 0, PARAM_INT);
-$sifirst = optional_param('sifirst', 'all', PARAM_ALPHA);
-$silast  = optional_param('silast', 'all', PARAM_ALPHA);
+$sifirst = optional_param('sifirst', 'all', PARAM_NOTAGS);
+$silast  = optional_param('silast', 'all', PARAM_NOTAGS);
 $start   = optional_param('start', 0, PARAM_INT);
 
 // Whether to show extra user identity information