libpurple in Pidgin 2.1.0 through 2.2.1, when using HTML logging, allows remote attackers to cause a denial of service (NULL dereference and application crash) via a message that contains invalid HTML data, a different vector than CVE-2007-4996.

libpurple in Pidgin before 2.2.1 does not properly handle MSN nudge messages from users who are not on the receiver's buddy list, which allows remote attackers to cause a denial of service (crash) via a nudge message that triggers an access of "an invalid memory location."