Suricata

If I got it right, the MIME part of SMTP messages is not parsed if the "BDAT" command is used for chunking.

In app-layer-smtp.c, the initialization of the MIME state data structure is only performed if the plain "DATA" command is used.
The SMTPProcessCommandBDAT function just seems to step over the lines following the BDAT command without any further processing.

If my observation is correct, I would like to suggest to implement it. If not, please close the ticket. Thanks.