Version 5.20 is a maintenance release that fixes critical security vulnerabilities and other bugs. Upgrading is strongly recommended. The security fixes include:

• A repair to a cross site request forgery vulnerability in the OpenID module.
• A solution to a vulnerability that could allow a user access to the account of another user when they share the same OpenID 2.0 provider.
• Security repairs for file uploads that are not correctly processed by the File API and could lead to the creation of files that are executable by Apache.
• A fix to a vulnerability that could allow a malicious user to reuse the session ID of another user.

For more details, see the release notes.