Synopsis
The remote mail server is vulnerable to a command execution attack.
Description
The remote host is running Exim, a message transfer agent.
Versions of Exim earlier than 4.76 are potentially affected by a format string vulnerability in logging DKIM information from an inbound email. By sending a specially crafted message to the server, a remote attacker can leverage this vulnerability to execute arbitrary code on the server subject to the privileges of the user running the affected application.
Solution
Upgrade to Exim 4.76 or later.