Accessible Open Source Content Management System - TYPOlight Open Source CMS
TYPOlight is an open source content management system (CMS) for people who want a professional internet presence that is easy to maintain. The state-of-the-art structure of the system offers a high security standard and allows you to develop search engine friendly websites that are also accessible for people with disabilities.
ApacheLenya - Content Management System
Apache Lenya is an Open Source Java/XML Content Management System and comes with revision control, multi-site management, scheduling, search, WYSIWYG editors, and workflow.
Frog CMS - Content Management Simplified
Frog CMS simplifies content management by offering an elegant user interface, flexible templating per page, simple user management and permissions, as well as the tools necessary for file management.
drupal.org - n open source content management platform
Drupal.org is the official website of Drupal, an open source content management platform. Equipped with a powerful blend of features, Drupal supports a variety of websites ranging from personal weblogs to large community-driven websites.