[MEDIUM] CVE-2019-10909: Escape validation messages in the PHP templating engine

PKSA-m1rn-sznw-gwbr CVE-2019-10909 GHSA-g996-q5r8-w7g2

Affected package: symfony/symfony

Affected version: >=2.7.0,<2.7.51|>=2.8.0,<2.8.50|>=3.0.0,<3.1.0|>=3.1.0,<3.2.0|>=3.2.0,<3.3.0|>=3.3.0,<3.4.0|>=3.4.0,<3.4.26|>=4.0.0,<4.1.0|>=4.1.0,<4.1.12|>=4.2.0,<4.2.7

Reported by:
GitHub, FriendsOfPHP/security-advisories