Possible XSS vulnerability in rails-html-sanitizer
There is a possible XSS vulnerability in the white list sanitizer in the
rails-html-sanitizer gem. This vulnerability has been assigned the CVE
Versions Affected: All.
Not affected: None.
Fixed Versions: v1.0.3
Carefully crafted strings can cause user input to bypass the sanitization in
the white list sanitizer which will can lead to an XSS attack.
Vulnerable code will look something like this:
<%= sanitize user_input, tags: %w(em) %>
All users running an affected release should either upgrade or use one of the
The FIXED releases are available at the normal locations.
Putting the following monkey patch in an initializer can help to mitigate the
alias :old_scrub :scrub
alias :old_skip_node? :skip_node?
text = node.document.create_text_node node.text
def skip_node?(node); node.text?; end
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
* 1-0-whitelist_sanitizer_xss.patch - Patch for 1.0 series
Thanks to Arnaud Germis, Nate Clark, and John Colvin for reporting this issue.