diff --git a/app/models/custom_emoji.rb b/app/models/custom_emoji.rb
index bd641a8579..1f3c1807ca 100644
--- a/app/models/custom_emoji.rb
+++ b/app/models/custom_emoji.rb
@@ -27,7 +27,7 @@ class CustomEmoji < ApplicationRecord
   LOCAL_LIMIT = (ENV['MAX_EMOJI_SIZE'] || 256.kilobytes).to_i
   LIMIT       = [LOCAL_LIMIT, (ENV['MAX_REMOTE_EMOJI_SIZE'] || 256.kilobytes).to_i].max
 
-  SHORTCODE_RE_FRAGMENT = '[a-zA-Z0-9_]{2,}'
+  SHORTCODE_RE_FRAGMENT = '(([[:alnum:]])|_){2,}'
 
   SCAN_RE = /(?<=[^[:alnum:]:]|\n|^)
     :(#{SHORTCODE_RE_FRAGMENT}):