Merge branch 'fix/sanitization-filter-leak' into 'master'

Fix a memory leak caused by Banzai::Filter::SanitizationFilter

See merge request !5808

CHANGELOG

@@ -108,6 +108,7 @@ v 8.11.0 (unreleased)
   - Sort folders with submodules in Files view !5521
   - Each `File::exists?` replaced to `File::exist?` because of deprecate since ruby version 2.2.0
   - Add auto-completition in pipeline (Katarzyna Kobierska Ula Budziszewska)
+  - Fix a memory leak caused by Banzai::Filter::SanitizationFilter
 
 v 8.10.5
   - Add a data migration to fix some missing timestamps in the members table. !5670

lib/banzai/filter/sanitization_filter.rb

@@ -7,7 +7,7 @@ module Banzai
       UNSAFE_PROTOCOLS = %w(data javascript vbscript).freeze
 
       def whitelist
-        whitelist = super
+        whitelist = super.dup
 
         customize_whitelist(whitelist)
 
@@ -42,6 +42,8 @@ module Banzai
         # Allow any protocol in `a` elements...
         whitelist[:protocols].delete('a')
 
+        whitelist[:transformers] = whitelist[:transformers].dup
+
         # ...but then remove links with unsafe protocols
         whitelist[:transformers].push(remove_unsafe_links)