Versions mentioned in the description apply to the upstream
Remediation section below for
Debian:10 relevant versions.
Exim 4 before 4.94.2 allows Integer Overflow to Buffer Overflow because get_stdinput allows unbounded reads that are accompanied by unbounded increases in a certain size variable. NOTE: exploitation may be impractical because of the execution time needed to overflow (multiple days).
exim4 to version 4.92-8+deb10u6 or higher.