USN-3579-1 fixed a vulnerability in LibreOffice. After upgrading, it was no longer possible for LibreOffice to open documents from certain locations outside of the user's home directory. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
It was discovered that =WEBSERVICE calls in a document could be used to read arbitrary files. If a user were tricked in to opening a specially crafted document, a remote attacker could exploit this to obtain sensitive information. (CVE-2018-6871)