Versions mentioned in the description apply to the upstream
Remediation section below for
Debian:9 relevant versions.
Exim 4 before 4.92 allows Integer Overflow to Buffer Overflow, in which an unauthenticated remote attacker can execute arbitrary code by leveraging the mishandling of continuation lines during header-length restriction.
exim4 to version 4.89-2+deb9u8 or higher.