Title: Weak Master Keys

Announced: July 25, 2022

Fixed in: LibreOffice 7.2.7/7.3.3


LibreOffice supports the storage of passwords for web connections in the user’s configuration database. The stored passwords are encrypted with a single master key provided by the user.

A flaw in LibreOffice existed where master key was poorly encoded resulting in weakening its entropy from 128 to 43 bits making the stored passwords vulnerable to a brute force attack if an attacker has access to the users stored config.

In versions >= 7.2.7 (and >= 7.3.3) the poor encoding is fixed and the user is prompted via an infobar to reenter their master password in order to reencrypt old existing vulnerable stored config data if it exists.


  • OpenSource Security GmbH on behalf of the German Federal Office for Information Security