CVE-2016-8562 in dovecot

[Aki Tuomi]

We are sorry to report that we have a bug in dovecot, which merits a
CVE. See details below. If you haven't configured any auth_policy_*
settings you are ok. This is fixed with
https://git.dovecot.net/dovecot/core/commit/c3d3faa4f72a676e183f34be960cff13a5a725ae
and
https://git.dovecot.net/dovecot/core/commit/99abb1302ae693ccdfe0d57351fd42c67a8612fc

Important vulnerability in Dovecot (CVE-2016-8562)
CVSS score: 7.4 (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H)
Affected version(s): 2.2.25.1 up to 2.2.26.1
Fixed in: 2.2.27.1rc1

Short summary: Dovecot auth component can be crashed by remote user when
auth-policy component is activated.

If auth-policy component has been activated in Dovecot, then remote user
can use SASL authentication to crash auth component.

Workaround is to disable auth-policy component until fix is in place.
This can be done by commenting out all auth_policy_* settings.

Aki Tuomi
Dovecot oy