Summary

If an account exists in JIRA that shares the e-mail address with one being used by a mail handler, the CC Assignee function will not work properly.

Steps to Reproduce

1. Configure a incoming mail server on the instance.
2. Create a mail handler with the CC Assignee function active.
3. Create a user account which uses the same e-mail address as the one used in the incoming mail server configuration.
4. Send a e-mail to create a issue in JIRA with a user's e-mail address as CC.

Expected Results

Issue is created and assigned to the CC'ed user.

Actual Results

Issue will be created and assigned to the account that shares the e-mail address with the incoming mail server configuration. This will be the case even if no user is set as the CC on the e-mail.

Note
Even if the user does not have any access to JIRA and is not set to be an assignable user, the incoming mail handler can still set the user as the assignee, see related bug: JRASERVER-65403

• This is due to granting "Assignable User" permission to "Application User - Any Logged in User"

Workaround

Change the e-mail address of the account that shares it with the mail server.