Maxthon Browser 3.0.0.145 Alpha with Ultramode does not properly block javascript: and data: URIs in Refresh headers in HTTP responses, which allows remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (1) injecting a Refresh header that contains a javascript: URI, (2) entering a javascript: URI when specifying the content of a Refresh header, (3) injecting a Refresh header that contains JavaScript sequences in a data:text/html URI, or (4) entering a data:text/html URI with JavaScript sequences when specifying the content of a Refresh header; does not properly block data: URIs in Location headers in HTTP responses, which allows user-assisted remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (5) injecting a Location header that contains JavaScript sequences in a data:text/html URI or (6) entering a data:text/html URI with JavaScript sequences when specifying the content of a Location header; and does not properly handle javascript: URIs in HTML links within (a) 301 and (b) 302 error documents sent from web servers, which allows user-assisted remote attackers to conduct cross-site scripting (XSS) attacks via vectors related to (7) injecting a Location HTTP response header or (8) specifying the content of a Location HTTP response header.