[Mailman-Users] Some subscriber's e-mail adresses contains linebreak unicode character ​

Henrik Rasmussen her at adm.ku.dk
Wed Oct 21 09:59:34 CEST 2015

Sorry, my bad. Output from list_members LISTNAME shows email addresses containing &#8203 like me at example.com&#8203, but without semicolon (;) used in HTML.

All the affected members seems to have been added by mass subscribtion from an admin so maybe the Mailman web interface form have been altered somewhere. I wonder why it's random though.

Thank you for the command. I will look further in to the problem.

Yours faithfully
Henrik Rasmussen
Systemadministrator, Core Services

> -----Oprindelig meddelelse-----
> Fra: Mailman-Users [mailto:mailman-users-
> bounces+her=adm.ku.dk at python.org] På vegne af Mark Sapiro
> Sendt: 21. oktober 2015 05:59
> Til: mailman-users at python.org
> Emne: Re: [Mailman-Users] Some subscriber's e-mail adresses contains
> linebreak unicode character 
> On 10/20/2015 01:52 AM, Henrik Rasmussen wrote:
> > In some occasions, a few subscribers of different lists contains the
> character ​ in the mail-address, like
> me at example.com​<mailto:me at example.com​> preventing
> them from receiving any mails from Mailman. The Unicode is always the
> same on affected subscribers.
> I am confused. Are you saying the addresses end with an actual Unicode zero
> width space character or that they end with the ascii string '​'. If the
> latter, I don't see how this can happen. In no version of Mailman 2.1 back to
> pre 2.1.1 has a ';' been allowed in an email address. If the former, an address
> with '\u200B' (the python escape for that character) in the domain would not
> have been allowed since Mailman 2.1.15, but may have been allowed before
> that.
> > As what I've read it is a zero space line break unicode character. So far the
> only think I found was about HTML pages containing the character and a
> single post explains something about the character being added to a page
> through the Office 365 Public Website editor. But since subscribing to a
> Mailman list does not involve an editor, I assume that the character could
> have been added by a webbased mail client.
> That is probably correct, but gmail's web mail in particular (which I once
> thought was good about stuff like this) and probably others when composing
> in 'rich text' and creating a multipart/alternative message, sometimes creates
> a text/plain alternative littered with these characters.
> Thus, if one composes an email in Gmail's web client to the list-request
> address with a body line
> subscribe me at example.com
> It is possible the text/plain alternative will have a zero width space appended
> to the address.
> > I don't know whether the subscribers have subscribed through mail or
> through the Mailman web interface, but since the problem is random, I
> assume that the Mailman web interface is not associated. I guess that it must
> be some kind of common web based MUA they have used, like Gmail or
> Hotmail or similar.
> Have you looked at Mailman's subscribe log?
> > What could course this and how can I prevent it?
> Conjecture on cause above. Prevention - upgrade Mailman to >= 2.1.15
> --
> Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
> San Francisco Bay Area, California    better use your sense - B. Dylan
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