MailMate before 1.11 automatically imported S/MIME certificates and thereby silently replaced existing ones. This allowed a man-in-the-middle attacker to obtain an email-validated S/MIME certificate from a trusted CA and replace the public key of the entity to be impersonated. This enabled the attacker to decipher further communication. The entire attack could be accomplished by sending a single email.

MailMate before 1.11.3 mishandles a suspicious HTML/MIME structure in a signed/encrypted email.

Common Vulnerabilities and Exposures assigned an identifier CVE-2008-0564 to the following vulnerability:

Multiple cross-site scripting (XSS) vulnerabilities in Mailman before 2.1.10b1 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors related to (1) editing templates and (2) the list's "info attribute" in the web administrator interface, a different vulnerability than CVE-2006-3636.

References: http://mail.python.org/pipermail/mailman-announce/2008-February/000096.html