The sm_close_on_exec function in conf.c in sendmail before 8.14.9 has arguments in the wrong order, and consequently skips setting expected FD_CLOEXEC flags, which allows local users to access unintended high-numbered file descriptors via a custom mail-delivery program.

sendmail before 8.14.4 does not properly handle a '\0' character in a Common Name (CN) field of an X.509 certificate, which (1) allows man-in-the-middle attackers to spoof arbitrary SSL-based SMTP servers via a crafted server certificate issued by a legitimate Certification Authority, and (2) allows remote attackers to bypass intended access restrictions via a crafted client certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Heap-based buffer overflow in Sendmail before 8.13.2 allows remote attackers to cause a denial of service (daemon crash) and possibly execute arbitrary code via a long X- header, as demonstrated by an X-Testing header.

mail.local in Sendmail 8.10.x does not properly identify the .\n string which identifies the end of message text, which allows a remote attacker to cause a denial of service or corrupt mailboxes via a message line that is 2047 characters long and ends in .\n.

Denial of service in Sendmail 8.6.11 and 8.6.12.

Sendmail 8.6.9 allows remote attackers to execute root commands, using ident.

Buffer overflow and denial of service in Sendmail 8.7.5 and earlier through GECOS field gives root access to local users.

In Sendmail, attackers can gain root privileges via SMTP by specifying an improper "mail from" address and an invalid "rcpt to" address that would cause the mail to bounce to a program.