Important: #100032 - Add HTTP security headers for backend by default

See forge#100032

Description

The following HTTP security headers are now added by default for the TYPO3 backend:

  • Strict-Transport-Security: max-age=31536000 (only if $GLOBALS[TYPO3_CONF_VARS][BE][lockSSL] is active)

  • X-Content-Type-Options: nosniff

  • Referrer-Policy: strict-origin-when-cross-origin

The default HTTP security headers are globally configured in $GLOBALS['TYPO3_CONF_VARS']['BE']['HTTP']['Response']['Headers'] and include a unique array key, so it is possible to individually unset/remove unwanted headers.

Important

TYPO3 websites, which already use custom HTTP headers for the TYPO3 backend, must ensure that individual HTTP security headers are not sent multiple times.