p5-Mail-SpamAssassin -- long message header denial of service

A Secunia Advisory reports:

A vulnerability has been reported in SpamAssassin, which can be exploited by malicious people to cause a DoS (Denial of Service).

The vulnerability is caused due to the use of an inefficient regular expression in "/SpamAssassin/Message.pm" to parse email headers. This can cause perl to crash when it runs out of stack space and can be exploited via a malicious email that contains a large number of recipients.

[source]