Improper Input Validation
If a user of Apache 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. Mitigation: Users should upgrade to Commons-Email 1.5. You can mitigate this vulnerability for older versions of Commons Email by stripping line-breaks from data, that will be passed to Email.setBounceAddress(String).
CWE-20 - Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.