cyrus-imapd: lmtpd component created mailboxes with administrator privileges if the "fileinto" was used, bypassing ACL checks

An issue was discovered in Cyrus IMAP before 2.5.15, 3.0.x before 3.0.13, and 3.1.x through 3.1.8. If sieve script uploading is allowed 3.x or certain non-default sieve options are enabled 2.x, a user with a mail account on the service can use a sieve script containing a fileinto directive to...