An XSS vulnerability in the escaping code used by Ruby on Rails was reported  where, using a specially crafted malformed unicode string, an attacker can bypass the escaping code. Due to a bug in the Ruby 1.8 regular expression code, the Ruby on Rails replacement for ERB::Util.h will fail to escape certain malformed unicode strings, which could then be interpreted as HTML by some browsers. This is corrected in upstream 3.0.10, 2.3.13, and 3.1.0rc5 versions and only affects platforms using Ruby 1.8.x (Ruby 1.9.x renders this ineffective).
Patches are available in the advisory  and in git .
This flaw is rubygems-activesupport, not rubygem-rails.
Created rubygem-activesupport tracking bugs for this issue
Affects: fedora-all [bug 731449]
Affects: epel-5 [bug 731450]
Affects: epel-6 [bug 731451]
This issue has been assigned the name CVE-2011-2932:
This issue has addressed in Fedora-14 and Fedora-15 via the following advisories:
rubygem-actionpack-2.3.18-1.el5, rubygem-activerecord-2.3.18-1.el5, rubygem-activesupport-2.3.18-1.el5 has been pushed to the Fedora EPEL 5 stable repository. If problems still persist, please make note of it in this bug report.