[MEDIUM] SS-2015-015: XSS in dev/build returnURL Parameter

PKSA-k8vj-swsf-842v GHSA-r3pr-fh25-wrfc

Affected package: silverstripe/framework

Affected version: >=3.1.0,<3.1.14

Reported by:
GitHub, FriendsOfPHP/security-advisories