USN-1059-1

A security issue affects the following Ubuntu releases:

Ubuntu 10.04 LTS
Ubuntu 10.10

This advisory also applies to the corresponding versions of
Kubuntu, Edubuntu, and Xubuntu.

The problem can be corrected by upgrading your system to the
following package versions:

Ubuntu 10.04 LTS:
dovecot-common 1:1.2.9-1ubuntu6.3

Ubuntu 10.10:
dovecot-common 1:1.2.12-1ubuntu8.1

In general, a standard system update will make all the necessary changes.

Details follow:

It was discovered that the ACL plugin in Dovecot would incorrectly
propagate ACLs to new mailboxes. A remote authenticated user could possibly
read new mailboxes that were created with the wrong ACL. (CVE-2010-3304)

It was discovered that the ACL plugin in Dovecot would incorrectly merge
ACLs in certain circumstances. A remote authenticated user could possibly
bypass intended access restrictions and gain access to mailboxes.
(CVE-2010-3706, CVE-2010-3707)

It was discovered that the ACL plugin in Dovecot would incorrectly grant
the admin permission to owners of certain mailboxes. A remote authenticated
user could possibly bypass intended access restrictions and gain access to
mailboxes. (CVE-2010-3779)

It was discovered that Dovecot incorrecly handled the simultaneous
disconnect of a large number of sessions. A remote authenticated user could
use this flaw to cause Dovecot to crash, resulting in a denial of service.
(CVE-2010-3780)