[MEDIUM] CVE-2019-12246: Denial of Service on flush and development URL tools

PKSA-9415-sntm-q9m8 CVE-2019-12246 GHSA-5fr8-xhqq-4p3q

Affected package: silverstripe/framework

Affected version: >=4.0.0,<4.4.0|>=4.1.0,<4.4.0|>=4.2.0,<4.4.0|>=4.3.0,<4.4.0

Reported by:
GitHub, FriendsOfPHP/security-advisories