Multiple cross-site scripting (XSS) vulnerabilities in the paste.httpexceptions implementation in Paste before 1.7.4 allow remote attackers to inject arbitrary web script or HTML via vectors involving a 404 status code, related to (1) paste.urlparser.StaticURLParser, (2) paste.urlparser.PkgResourcesParser, (3) paste.urlmap.URLMap, and (4) HTTPNotFound.