Microsoft has released the Microsoft Office for Mac 2011 14.5.0 Update. (113.6 MB) Installation requires first installing the cumulative 14.1.0 (SP1) update if running an earlier version of Office for Mac 2011.
According to the new update’s description it addresses a security vulnerability that could allow code to run when opening a specially crafted Excel, PowerPoint or Word document. Typically, these vulnerabilities do not affect Macs, however, an update may correct issues in the Office for Mac applications to prevent crafting malicious documents.
This update does break Outlook for Mac 2011 running on Yosemite (10.10.x). Mavericks (10.9.5) and earlier supported systems are not affected.
Users should quit all Office applications and web browsers prior to updating. This update is also available via the Microsoft AutoUpdate application. Select Check for Updates from the Help menu. It is also available for immediate download.