Of course bash doesn't know and shouldn't know about the SMTP RFCs. Yes, bash shouldn't execute code in variables. I was talking about input validation in qmail itself, not bash.
Even though bash shouldn't have executed the code, better input validation and RFC conformance in qmail could have prevented exploitation of bash. You know, defense-in-depth.
Even though bash shouldn't have executed the code, better input validation and RFC conformance in qmail could have prevented exploitation of bash. You know, defense-in-depth.