Versions mentioned in the description apply to the upstream
Remediation section below for
Debian:10 relevant versions.
Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters, relevant in non-default configurations that enable Delivery Status Notification (DSN). Certain uses of ORCPT= can place a newline into a spool header file, and indirectly allow unauthenticated remote attackers to execute arbitrary commands as root.
exim4 to version 4.92-8+deb10u6 or higher.