Debian DSA-4745-1: Dovecot Critical Update - DoS And Buffer Overflow

CVE-2020-12100

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 the stable distribution (buster), these problems have been fixed in
version 1:2.3.4.1-5+deb10u3.

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 Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/