When using a mail handler with Default Reporter set and a user that does not have permission to create an issue tries to create one via mail, that issue is never created and the following error appears on atlassian-jira-incoming-mail.log:

2014-11-20 17:20:57,806 WARN [Atlassian] atlassian-scheduler-quartz1.clustered_Worker-1 ServiceRunner    Create Issue Create Issue[10000]: Reporter (jirauser) does not have permission to create an issue. Message rejected.

This doesn't make much sense when you consider anyone else can create the issue via email, except users that are in JIRA but without the necessary permissions.

Steps to reproduce
Set a mail handler to create issues with Default Reporter
Send mail to the handler from a user without permissions to create issue on the project

Expected behavior
Default reporter creates the issue with it's own credential on behalf of that user.

Actual Behavior
Message is rejected because user does have permission to create it.

If we have the group "Anyone" in the permissions the problem still happens for disabled users