The CGI module in Ruby 1.6 before 1.6.8, and 1.8 before 1.8.2, allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a certain HTTP request.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10268
https://exchange.xforce.ibmcloud.com/vulnerabilities/17985
http://www.securityfocus.com/bid/11618
http://www.redhat.com/support/errata/RHSA-2004-635.html
http://www.mandriva.com/security/advisories?name=MDKSA-2004:128