[Dovecot] Sieve rule issue with certain character sets

[Thomas Leuxner]

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I have a global sieve rule in place to filter mailing-lists. This has worked well so far. Recently however one subscriber on a list seems to create strange character set encodings in the 'From' and 'To' headers. This leads to unprocessed/unfiltered mails (no errors thrown). Is this a configuration or Pigeonhole issue (latest HG used)?

Headers from failing mail:

From: "=?UTF-8?B?VG9yaW50aGllbA==?=" <user at domain.tld>
To: "=?UTF-8?B?ImJpbmQtdXNlcnNAbGlzdHMuaXNjLm9yZyI=?="
	<bind-users at lists.isc.org>

Relevant sieve rule:

if allof (address :is ["To","CC"] ["bind-users at lists.isc.org","bind-users at isc.org","comp-protocols-dns-bind at isc.org"],
        header :contains "List-Id" "bind-users.lists.isc.org")
        {
        fileinto "Public/Mailing-Lists/Bind-Users";
        }

Regards
Thomas

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