Debian 9 DLA-2328-1 Critical: Dovecot Email Server Security Issues

Receiving mail with deeply nested MIME parts leads to resource
exhaustion as Dovecot attempts to parse it.

CVE-2020-12673

Dovecot's NTLM implementation does not correctly check message
buffer size, which leads to a crash when reading past allocation.

CVE-2020-12674

Dovecot's RPA mechanism implementation accepts zero-length message,
which leads to assert-crash later on.

For Debian 9 stretch, these problems have been fixed in version
1:2.2.27-3+deb9u6.

We recommend that you upgrade your dovecot packages.

For the detailed security status of dovecot please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/dovecot

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS