The Issues API in Redmine before 2.6.8, 3.0.x before 3.0.6, and 3.1.x before 3.1.2 allows remote authenticated users to obtain sensitive information in changeset messages by leveraging permission to read issues with related changesets from other projects.
https://www.redmine.org/versions/105
https://www.redmine.org/projects/redmine/wiki/Changelog_3_1
https://www.redmine.org/projects/redmine/wiki/Changelog_3_0
https://www.redmine.org/issues/21136
https://github.com/redmine/redmine/commit/8d8f612fa368a72c56b63f7ce6b7e98cab9feb22
https://euvd.enisa.europa.eu/vulnerability/EUVD-2015-8355