Moodle 2.3.x before 2.3.1 uses only a client-side check for whether references are permitted in a file upload, which allows remote authenticated users to bypass intended alias (aka shortcut) restrictions via a client that omits this check.
git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-33948
openwall.com/lists/oss-security/2012/07/17/1
exchange.xforce.ibmcloud.com/vulnerabilities/76954
github.com/moodle/moodle
github.com/moodle/moodle/commit/3b6629c088f14c6ee8f13a009ff27441d164f334
github.com/moodle/moodle/commit/61a339e59857fd36080f4a468a16cd6a539d90bb
nvd.nist.gov/vuln/detail/CVE-2012-3387
web.archive.org/web/20121104220059/www.securityfocus.com/bid/54481