Sanitize `vbscript:` links

Closes https://dev.gitlab.org/gitlab/gitlabhq/issues/2660

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/banzai/filter/sanitization_filter.rb b/lib/banzai/filter/sanitization_filter.rb
index c201ace8d35..abd79b329ae 100644
--- a/lib/banzai/filter/sanitization_filter.rb
+++ b/lib/banzai/filter/sanitization_filter.rb
@@ -7,6 +7,8 @@ module Banzai
     #
     # Extends HTML::Pipeline::SanitizationFilter with a custom whitelist.
     class SanitizationFilter < HTML::Pipeline::SanitizationFilter
+      UNSAFE_PROTOCOLS = %w(javascript :javascript data vbscript).freeze
+
       def whitelist
         whitelist = super
 
@@ -62,7 +64,7 @@ module Banzai
           return unless node.name == 'a'
           return unless node.has_attribute?('href')
 
-          if node['href'].start_with?('javascript', ':javascript', 'data')
+          if node['href'].start_with?(*UNSAFE_PROTOCOLS)
             node.remove_attribute('href')
           end
         end