Session fixation vulnerability in Rails before 1.2.4, as used for Ruby on Rails, allows remote attackers to hijack web sessions via unspecified vectors related to "URL-based sessions."

Rails before 1.2.4, as used for Ruby on Rails, allows remote attackers and ActiveResource servers to determine the existence of arbitrary files and read arbitrary XML files via the Hash.from_xml (Hash#from_xml) method, which uses XmlSimple (XML::Simple) unsafely, as demonstrated by reading passwords from the Pidgin (Gaim) .purple/accounts.xml file.