In general, Ember.js escapes or strips any user-supplied content before inserting it in strings that will be sent to innerHTML. However, the `tagName` property of an `Ember.View` was inserted into such a string without being sanitized. This means that if an application assigns a view's `tagName` to user-supplied data, a specially-crafted payload could execute arbitrary JavaScript in the context of the current domain ("XSS"). This vulnerability only affects applications that assign or bind user-provided content to `tagName`.

Ember.js 1.0.x before 1.0.1, 1.1.x before 1.1.3, 1.2.x before 1.2.1, 1.3.x before 1.3.1, and 1.4.x before 1.4.0-beta.2 allows remote attackers to conduct cross-site scripting (XSS) attacks by leveraging an application using the "{{group}}" Helper and a crafted payload.

Ember.js 1.0.x before 1.0.1, 1.1.x before 1.1.3, 1.2.x before 1.2.1, 1.3.x before 1.3.1, and 1.4.x before 1.4.0-beta.2 allows remote attackers to conduct cross-site scripting (XSS) attacks by leveraging an application that contains templates whose context is set to a user-supplied primitive value and also contain the `{{this}}` special Handlebars variable.