Breaking: #93002 - Support for session transfer via FE_SESSION_KEY removed

See Issue #93002

Description

TYPO3s Frontend Session Handling has had a custom feature by setting a custom GET variable called FE_SESSION_KEY to inject an existing session into a Frontend Request without having a cookie sent as response.

This seldom used feature, which was limited to Frontend sessions only, and required knowledge of third-party integrations for TYPO3s encryption key to create such a session key is removed.

Features for integrating sessions should instead be built with custom AuthenticationServices, e.g. for Single-Sign-On functionality.

Impact

Calling TYPO3s Frontend with FE_SESSION_KEY as GET parameter has no effect anymore and will not pick up an existing session.

Affected Installations

TYPO3 installations using this FE_SESSION_KEY which is very rare and unlikely to be used.

Migration

Build a custom Authentication Service to log in and use user session instead in a third-party extension.