wordpress -- multiple vulnerabilities

The wordpress development team reports:

Block unsafe PHP unserialization that could occur in limited
situations and setups, which can lead to remote code
execution.
Prevent a user with an Author role, using a specially crafted
request, from being able to create a post “written by” another
user.
Fix insufficient input validation that could result in
redirecting or leading a user to another website.

Additionally, we’ve adjusted security restrictions around file
uploads to mitigate the potential for cross-site scripting.