LTI reject non-numeric value in replace service - refs BT#13469

plugin/ims_lti/src/ImsLtiServiceReplaceRequest.php

@@ -26,7 +26,17 @@ class ImsLtiServiceReplaceRequest extends ImsLtiServiceRequest
     {
         $resultRecord = $this->xmlRequest->resultRecord;
         $sourcedId = (string) $resultRecord->sourcedGUID->sourcedId;
-        $resultScore = (float) $resultRecord->result->resultScore->textString;
+        $resultScore = (string) $resultRecord->result->resultScore->textString;
+
+        if (!is_numeric($resultScore)) {
+            $this->statusInfo
+                ->setSeverity(ImsLtiServiceResponseStatus::SEVERITY_ERROR)
+                ->setCodeMajor(ImsLtiServiceResponseStatus::CODEMAJOR_FAILURE);
+
+            return;
+        }
+
+        $resultScore = (float) $resultScore;
 
         if (0 > $resultScore || 1 < $resultScore) {
             $this->statusInfo