I have come across an issue with shopping cart promotions on our site. It seems as though there is a patch, SUPEE-4814, to resolve this, but I can't find it on the https://magento.com/security/patches.
I have found links to this patch on GitHub (https://gist.github.com/piotrekkaminski/54529dadb0bc01a62a2d), but I don't know anything about the author. Is it a genuine patch?