When a user shares a Jira issue with external users, 2 things happen:

1. The user(s) will receive an email with the title of the issue/page shared in it and a link to what is being shared.
2. If the user access settings allow it, and the user receiving the email has an email address that is not yet added to the site, they will also have the opportunity to add themselves to the site.

For step 2, it is possible to prevent users from self-signing through the change in the User access settings: User invites, but step 1 can't be prevented so any user can use the share function and share the issue/page name and link, even if the user receiving the email does not actually have permissions to access the link received. This could be considered a form of data leak.

The suggestion is to have the ability to entirely disable the 'Share issue' function from Issues or projects to external users.

• A very similar request but for being able to disable the sharing from Software boards also exists at JSWCLOUD-26092: Allow to disable the share button on boards.