Apache Commons-Email, from version 1.0 to 1.4 inclusive, does not properly validate bounce addresses. If a user of Commons-Email (typically an application programmer) passes unvalidated input as the so-called "Bounce Address", and that input contains line-breaks, then the email details (recipients, contents, etc.) might be manipulated.
Created apache-commons-email tracking bugs for this issue:
Affects: fedora-all [bug 1540001]