diff --git a/lib/rubygems/version.rb b/lib/rubygems/version.rb
index 2ced9cc..2fd0ab4 100644
--- a/lib/rubygems/version.rb
+++ b/lib/rubygems/version.rb
@@ -145,7 +145,7 @@ class Gem::Version
 
   include Comparable
 
-  VERSION_PATTERN = '[0-9]+(\.[0-9a-zA-Z]+)*' # :nodoc:
+  VERSION_PATTERN = '[0-9]+(?>\.[0-9a-zA-Z]+)*' # :nodoc:
   ANCHORED_VERSION_PATTERN = /\A\s*(#{VERSION_PATTERN})*\s*\z/ # :nodoc:
 
   ##
-- 
1.8.4