Cross-site scripting (XSS) vulnerability in Hypermail 2.2.0 allows remote attackers to inject arbitrary web script or HTML via a crafted From address, which is not properly handled when indexing messages.

Multiple buffer overflows in Hypermail 2 before 2.1.6 allows remote attackers to cause a denial of service and possibly execute arbitrary code (1) via a long attachment filename that is not properly handled by the hypermail executable, or (2) by connecting to the mail CGI program from an IP address that reverse-resolves to a long hostname.

Hypermail allows remote attackers to execute arbitrary commands on a server supporting SSI via an attachment with a .shtml extension, which is archived on the server and can then be executed by requesting the URL for the attachment.