The /rest/api/2/user/picker rest resource in Jira before version 7.13.3, from version 8.0.0 before version 8.0.4, and from version 8.1.0 before version 8.1.1 allows remote attackers to enumerate usernames via an incorrect authorisation check.
The BrowseProjects.jspa resource in Jira before version 7.13.2, and from version 8.0.0 before version 8.0.2 allows remote attackers to see information for archived projects through a missing authorisation check.