Hi everyone,

Here is the story. We are running Redhat Enterprise Linux 4, and were using Dovecot .99.x . At one point, we chose to switch from mbox to maildir (and still use Dovecot). After the switchover our users reported a bug when using Thunderbird:

"A new behavior that I have observed a couple of times is that the new IMAP server confuses email headers with content. E.g., I have an email from Person X, but when I go to view it, the contents is just a spam body from an adjacent header. With this specific bug, adjacent spams are also running into other bodies. This occurs I'd say once every hundred messages. Other appearances of this bug are with adjacent messages concatenated.

I'm not sure how to explain this, maybe what happens is that the new IMAP server confuses requests and delivers the wrong message bodies to the client, which get cached.

This could in some circumstances be more than an annoyance, e.g., with confidential emails inadvertently getting picked up in replies to people outside the company."

We proceeded to update Dovecot to the latest available version (1.0.0-rc25). However, despite that, our users still report the same bug:

"This bug still persists. In particular, I just (after the new version was applied) clicked on an email from Person X, and Thunderbird displayed an email from Person Y that I had just replied to. Note that the email from Y was not adjacent to the one from X (at least, in the temporal ordering)."

I have not been able to reproduce the bug myself. Can anyone think of where we should start debugging?

Best regards, Andrey Falko