When two issues are linked together in JIRA by one user, but the linked issue is not visible for a second user, then the issuekey of the linked issue still will be leaked to that second user, using the History Tab.

Steps to reproduce:

• User A creates Issue 1. This issue is visible to User A and User B.
• User A creates Issue 2. This issue is visible to User A and User C.
• User A (who has rights on both issues), links issue 1 to issue 2.
• Note that User B does not have any rights on the issue or project in witch issue 2 is created.
• User C opens issue 2
  • In the main view of the issue, no reference to Issue 1 is shown (this is correct)
  • When the user clicks the History tab, there is a reference to Issue 2 (this is incorrect, and should not be visible)