diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index ace6a1b..64289f4 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1082,7 +1082,7 @@ function template_preprocess_item_list(&$variables) {
 function template_preprocess_inline_list(&$variables) {
   // Since the separator may be user-specified, it must be filtered to permit
   // some HTML (such as <br />) to pass through.
-  $variables['separator'] = SafeString::create(Xss::filterAdmin($variables['separator']));
+  $variables['separator'] = SafeString::create(Xss::filter($variables['separator'], ['br']));
 }
 
 /**
diff --git a/core/modules/system/src/Tests/Theme/FunctionsTest.php b/core/modules/system/src/Tests/Theme/FunctionsTest.php
index 2910692..4442986 100644
--- a/core/modules/system/src/Tests/Theme/FunctionsTest.php
+++ b/core/modules/system/src/Tests/Theme/FunctionsTest.php
@@ -189,21 +189,21 @@ function testInlineList() {
     $expected = 'Rabbit, rabbit, rabbit';
     $this->assertThemeOutput('inline_list', $variables, $expected, '%callback does not print empty text when there are list items.');
 
-    // Verify that a non-default separator is rendered
+    // Verify that a non-default separator is rendered.
     $variables = array();
     $variables['items'] = array('Un', 'Deux', 'Trois');
     $variables['separator'] = ' and ';
     $expected = 'Un and Deux and Trois';
     $this->assertThemeOutput('inline_list', $variables, $expected, '%callback uses a custom separator when provided.');
 
-    // Verify that HTML separators are properly rendered
+    // Verify that HTML separators are properly rendered.
     $variables = array();
     $variables['items'] = array('Doe', 'Buck', 'Kit');
     $variables['separator'] = '<br />';
     $expected = 'Doe<br />Buck<br />Kit';
     $this->assertThemeOutput('inline_list', $variables, $expected, '%callback allows HTML in user-provided separators.');
 
-    // Verify that the separator is sanitized
+    // Verify that the separator is sanitized.
     $variables = array();
     $variables['items'] = array('Un', 'Deux', 'Trois');
     $variables['separator'] = '<script>alert("test")</script>';