diff --git a/htdocs/comm/action/index.php b/htdocs/comm/action/index.php
index 6e23e6d0a93..6f24008c7ad 100644
--- a/htdocs/comm/action/index.php
+++ b/htdocs/comm/action/index.php
@@ -1384,9 +1384,9 @@ if (count($listofextcals)) {
 					$event->datep = $datestart + $usertime;
 					$event->datef = $dateend + $usertime;
 
-					if ($icalevent['SUMMARY']) {
+					if (isset($icalevent['SUMMARY']) && $icalevent['SUMMARY']) {
 						$event->label = dol_string_nohtmltag($icalevent['SUMMARY']);
-					} elseif ($icalevent['DESCRIPTION']) {
+					} elseif (isset($icalevent['DESCRIPTION']) && $icalevent['DESCRIPTION']) {
 						$event->label = dol_nl2br(dol_string_nohtmltag($icalevent['DESCRIPTION']), 1);
 					} else {
 						$event->label = $langs->trans("ExtSiteNoLabel");