[MEDIUM] SS-2017-006: Session user agent change detection

PKSA-qgw5-v9gv-s75z GHSA-m8v7-x398-pxrf

Affected package: silverstripe/framework

Affected version: >=3.5.0,<3.5.6|>=3.6.0,<3.6.3

Reported by:
GitHub, FriendsOfPHP/security-advisories