It was discovered that moin, a python clone of WikiWiki, does not sufficiently sanitize parameters when passing them to the add_msg function. This allows a remote attackers to conduct cross-site scripting (XSS) attacks for example via the template parameter.
For the stable distribution (lenny), this problem has been fixed in version 1.7.1-3+lenny5.
For the testing distribution (squeeze), this problem will be fixed soon.
For the unstable distribution (sid), this problem has been fixed in version 1.9.3-1.