Cross-site scripting (XSS) vulnerability in libahttp/err.c in OkCupid OKWS (OK Web Server) allows remote attackers to inject arbitrary web script or HTML via the PATH_INFO to a non-existent page, which is not properly handled in a 404 error page.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.