[Tickets #11718] Imp does not always create a valid subtype

[bugs at horde.org]

DO NOT REPLY TO THIS MESSAGE. THIS EMAIL ADDRESS IS NOT MONITORED.

Ticket URL: http://bugs.horde.org/ticket/11718
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  Ticket             | 11718
  Created By         | peter.meier+horde at immerda.ch
  Summary            | Imp does not always create a valid subtype
  Queue              | IMP
  Version            | 5.0.23
  Type               | Bug
  State              | Unconfirmed
  Priority           | 1. Low
  Milestone          |
  Patch              |
  Owners             |
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peter.meier+horde at immerda.ch (2012-11-17 11:50) wrote:

The following part is an excerpt of a Mail Header sent by IMP, where  
the charset in the content-type is empty.

----
User-Agent: Internet Messaging Program (IMP) H4 (5.0.23)
Content-Type: text/plain; charset=; format=flowed; DelSp=Yes
MIME-Version: 1.0
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
---

This happened when somebody replies to a message she could not decrypt.

According to RFC1521 [1] a value of a subtype must be specified, so  
IMP produces here imho an invalid message.

I can reproduce it if I try to open an E-Mail I can't decrypt (because  
I don't have the right OpenPGP key for it) and reply to that e-mail.  
-> The e-mail sent does not specifiy a value for the charset subtype  
of the Content-Type header field.

Also various e-mail parsing tools detect such a header as invalid.

[1] https://datatracker.ietf.org/doc/rfc1521/