為Web帶來下一代媒體體驗和豐富的交互式應用程序體驗。做為微軟出品的一個瀏覽器增強模塊，它使得瀏覽器可以在HTML中渲染豐富的內容，它兼容于Windows下的IE以及Firefox等瀏覽器，同時也兼容Mac OS X。雖然隨著新系統的發布及HTML5的逐漸運用，Silverlight在微軟的重要性正在降低，微軟依然在持續更新版本。

　　此次主要修復了一些安全問題和版本更新，以及Silverlight插件在Mac OS X可能導致的崩潰和異常處理。

　　- Fixes security issues described in the following Microsoft Knowledge Base article: 2847559 MS13-052

　　- Fixes an issue where core CLR files were versioned as 5.0, and the System.Environment.Version public API reported the Silverlight framework version as 5.0. With this fix, all CLR and Silverlight files now have a major and minor file version of 5.1, and Environment.Version reports 5.1 as the framework version.

　　- Fixes an issue where certain buffered web requests can cause a crash of the Silverlight plugin on Mac OS X.

　　- Enables Silverlight application exception handling on future releases of Mac OS X.