Mime prepare email message body error

[triada63]

Bug Report

Q	A
Version(s)	2.24.0

Summary

Problem when sending an email that has a link to the store "". Occurs in a specific situation where the laminas-mime module slices the text of a message, and "to:" may appear at the beginning of a line. Then the mail server thinks that it is necessary to send a letter to this address, and gives:
ssmtp: RCPT TO: *** (555 5.5.2 Syntax error)

Current behavior

It is necessary to check and escape the presence of special words at the beginning of each line

How to reproduce

add '' to body of mail, add some characters for show "to:" in begginning of line, and use "quoted-printable" encoding method.

Expected behavior

[Slamdunk]

and "to:" may appear at the beginning of a line. Then the mail server thinks that it is necessary to send a letter to this address

That would be a very wierd server then: the e-mail standard tells that the first two-newline sequence breaks the headers from the body, and the body shall never be used as a source of truth for any header-like purpose.

As far as I can tell, I see no bug here

[triada63]

and "to:" may appear at the beginning of a line. Then the mail server thinks that it is necessary to send a letter to this address

That would be a very wierd server then: the e-mail standard tells that the first two-newline sequence breaks the headers from the body, and the body shall never be used as a source of truth for any header-like purpose.

As far as I can tell, I see no bug here

I thought so too. But i debug it in project. This code in Magento 2 project, which uses laminas-mail for send order mails, it use base php mail() function for send in laminas Transport/Sendmail:send($message), headers and body sending separately, but wrong "to:" is still taken from the message body.