A potential denial of service problem has been found in sendmail.
A malformed MIME message could trigger excessive recursion which
will lead to stack exhaustion. This denial of service attack only
affects delivery of mail from the queue and delivery of a malformed
message. Other incoming mail is still accepted and delivered.
However, mail messages in the queue may not be reattempted if a
malformed MIME message exists.
Patches for the respective releases: