From a7cda7e6aa5334ab41b1f4b0f671be931be946ef Mon Sep 17 00:00:00 2001
From: John Hawthorn <john@hawthorn.email>
Date: Wed, 11 Jan 2023 10:14:55 -0800
Subject: [PATCH] Avoid regex backtracking in Inflector.underscore

[CVE-2023-22796]
---
 activesupport/lib/active_support/inflector/methods.rb | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/activesupport-5.2.4.4/lib/active_support/inflector/methods.rb b/activesupport-5.2.4.4/lib/active_support/inflector/methods.rb
index ad136532bf..acb86fe1a4 100644
--- a/activesupport-5.2.4.4/lib/active_support/inflector/methods.rb
+++ b/activesupport-5.2.4.4/lib/active_support/inflector/methods.rb
@@ -93,8 +93,7 @@ def underscore(camel_cased_word)
       return camel_cased_word unless /[A-Z-]|::/.match?(camel_cased_word)
-      word = camel_cased_word.to_s.gsub("::".freeze, "/".freeze)
-      word.gsub!(inflections.acronyms_underscore_regex) { "#{$1 && '_'.freeze }#{$2.downcase}" }
+      word = camel_cased_word.to_s.gsub("::", "/")   
+      word.gsub!(inflections.acronyms_underscore_regex) { "#{$1 && '_' }#{$2.downcase}" } 
-      word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2'.freeze)
-      word.gsub!(/([a-z\d])([A-Z])/, '\1_\2'.freeze)
+      word.gsub!(/([A-Z])(?=[A-Z][a-z])|([a-z\d])(?=[A-Z])/) { ($1 || $2) << "_" }
-      word.tr!("-".freeze, "_".freeze)
+      word.tr!("-", "_")
       word.downcase!
       word
-- 
2.35.1

