1 files changed, 24 insertions, 12 deletions
diff --git a/app/models/concerns/taskable.rb b/app/models/concerns/taskable.rb
index f9eba4cc2fe..dee1c820f23 100644
--- a/app/models/concerns/taskable.rb
+++ b/app/models/concerns/taskable.rb
@@ -24,25 +24,37 @@ module Taskable
     (\s.+)                        # followed by whitespace and some text.
   }x.freeze
 
+  ITEM_PATTERN_UNTRUSTED =
+    '^' \
+    '(?:(?:>\s{0,4})*)' \
+    '(?P<prefix>(?:\s*(?:[-+*]|(?:\d+\.)))+)' \
+    '\s+' \
+    '(?P<checkbox>' \
+    "#{COMPLETE_PATTERN.source}|#{INCOMPLETE_PATTERN.source}" \
+    ')' \
+    '(?P<label>\s.+)'.freeze
+
   # ignore tasks in code or html comment blocks.  HTML blocks
   # are ok as we allow tasks inside <detail> blocks
-  REGEX = %r{
-      #{::Gitlab::Regex.markdown_code_or_html_comments}
-    |
-      (?<task_item>
-        #{ITEM_PATTERN}
-      )
-  }mx.freeze
+  REGEX =
+    "#{::Gitlab::Regex.markdown_code_or_html_comments_untrusted}" \
+    "|" \
+    "(?P<task_item>" \
+    "#{ITEM_PATTERN_UNTRUSTED}" \
+    ")".freeze
 
   def self.get_tasks(content)
     items = []
 
-    content.to_s.scan(REGEX) do
-      next unless $~[:task_item]
+    regex = Gitlab::UntrustedRegexp.new(REGEX, multiline: true)
+    regex.scan(content.to_s).each do |match|
+      next unless regex.extract_named_group(:task_item, match)
+
+      prefix = regex.extract_named_group(:prefix, match)
+      checkbox = regex.extract_named_group(:checkbox, match)
+      label = regex.extract_named_group(:label, match)
 
-      $~[:task_item].scan(ITEM_PATTERN) do |prefix, checkbox, label|
-        items << TaskList::Item.new("#{prefix.strip} #{checkbox}", label.strip)
-      end
+      items << TaskList::Item.new("#{prefix.strip} #{checkbox}", label.strip)
     end
 
     items