Debian: DSA-4611-1 Urgent OpenSMTPD Command Execution and TLS Downgrade

Qualys discovered that the OpenSMTPD SMTP server performed insufficient
validation of email addresses which could result in the execution of
arbitrary commands as root. In addition this update fixes a denial of
service by triggering an opportunistic TLS downgrade.

For the oldstable distribution (stretch), these problems have been fixed
in version 6.0.2p1-2+deb9u2.

For the stable distribution (buster), these problems have been fixed in
version 6.0.3p1-5+deb10u3. This update also includes non-security
bugfixes which were already lined up for the Buster 10.3 point release.

We recommend that you upgrade your opensmtpd packages.

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

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/