Mozilla Firefox before 3.0.9 and SeaMonkey 1.1.17 do not block javascript: 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 or (2) specifying the content of a Refresh header. NOTE: it was later reported that Firefox 3.6 a1 pre and Mozilla 1.7.x and earlier are also affected.