The prescan() function in the address parser (parseaddr.c) in Sendmail before 8.12.9 does not properly handle certain conversions from char and int types, which can cause a length check to be disabled when Sendmail misinterprets an input value as a special "NOCHAR" control value, allowing attackers to cause a denial of service and possibly execute arbitrary code via a buffer overflow attack using messages, a different vulnerability than CVE-2002-1337.

The metamail package allows remote command execution using shell metacharacters that are not quoted in a mailcap entry.

Sendmail allows local users to write to a file and gain group permissions via a .forward or :include: file.