Versions mentioned in the description apply to the upstream
Remediation section below for
Debian:10 relevant versions.
Exim 4 before 4.94.2 allows Out-of-bounds Write because the main function, while setuid root, copies the current working directory pathname into a buffer that is too small (on some common platforms).
exim4 to version 4.92-8+deb10u6 or higher.