jquery_ujs.js in jquery-rails before 3.1.3 and 4.x before 4.0.4 and rails.js in jquery-ujs before 1.0.4, as used with Ruby on Rails 3.x and 4.x, allow remote attackers to bypass the Same Origin Policy, and trigger transmission of a CSRF token to a different-domain web server, via a leading space character in a URL within an attribute value.

References

• https://nvd.nist.gov/vuln/detail/CVE-2015-1840
• GHSA-4whc-pp4x-9pf3
• https://github.com/rails/jquery-rails/blob/master/CHANGELOG.md
• https://github.com/rails/jquery-ujs/blob/master/CHANGELOG.md
• https://groups.google.com/forum/message/raw?msg=rubyonrails-security/XIZPbobuwaY/fqnzzpuOlA4J
• http://lists.fedoraproject.org/pipermail/package-announce/2015-June/160906.html
• http://lists.fedoraproject.org/pipermail/package-announce/2015-June/161043.html
• http://lists.opensuse.org/opensuse-updates/2015-07/msg00041.html
• http://openwall.com/lists/oss-security/2015/06/16/15
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/jquery-ujs/CVE-2015-1840.yml
• https://groups.google.com/forum/#!topic/ruby-security-ann/XIZPbobuwaY
• https://web.archive.org/web/20200228084945/http://www.securityfocus.com/bid/75239