XSS Vulnerability in number_to_currency
There is an XSS vulnerability in the number_to_currency helper in Ruby on Raile. This vulnerability has been assigned the CVE identifier CVE-2013-6415.
Versions Affected: All.
Fixed Versions: 4.0.2, 3.2.16.
The number_to_currency helper allows users to nicely format a numeric value. One of the parameters to the helper (unit) is not escaped correctly. Application which pass user controlled data as the unit parameter are vulnerable to an XSS attack.
All users passing user controlled data as number_to_currency's unit parameters should either upgrade or use one of the workarounds immediately.
The 4.0.2 and 3.2.16 releases are available at the normal locations.
The workaround for this issue is to escape the value passed to the :unit parameter. For example, replace code like this:
<%= number_to_currency(1.02, unit: params[:currency]) %>
With code like this
<%= number_to_currency(1.02, unit: h(params[:currency])) %>
To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.
* 4-0-number_to_currency_xss.patch - Patch for 4.0 series
* 3-2-number_to_currency_xss.patch - Patch for 3.2 series
Please note that only the 4.0.x and 3.2.x series are supported at present. Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases.
Thanks to Ankit Gupta for reporting the issue to us and working with us on a fix.