web-app.org WebAPP before 0.9.9.6 allows remote authenticated users to upload certain files (1) via a crafted filename or (2) by "using percent encoding in forms."
http://www.web-app.org/cgi-bin/index.cgi?action=viewnews&id=254
http://www.web-app.org/cgi-bin/index.cgi?action=viewnews&id=252
http://www.vupen.com/english/advisories/2007/0720
http://www.attrition.org/pipermail/vim/2007-March/001455.html