The nsDocument::MaybePreLoadImage function in content/base/src/nsDocument.cpp in the image-preloading implementation in Mozilla Firefox 3.6 before 3.6.2 does not apply scheme restrictions and policy restrictions to the image's URL, which might allow remote attackers to cause a denial of service (application crash or hang) or hijack the functionality of the browser's add-ons via a crafted SRC attribute of an IMG element, as demonstrated by remote command execution through an ssh: URL in a configuration that supports gnome-vfs with a nonstandard network.gnomevfs.supported-protocols setting.