The jira.editor.user.mode cookie set by the Jira Editor Plugin in Jira Server and Data Center before version 8.5.12, from version 8.6.0 before version 8.13.4, and from version 8.14.0 before version 8.15.0 allows remote anonymous attackers who can perform an attacker in the middle attack to learn which mode a user is editing in due to the cookie not being set with a secure attribute if Jira was configured to use https.