FrankenPHP is a modern application server for PHP. Prior to 1.11.2, when running FrankenPHP in worker mode, the $_SESSION superglobal is not correctly reset between requests. This allows a subsequent request processed by the same worker to access the $_SESSION data of the previous request (potentially belonging to a different user) before session_start() is called. This vulnerability is fixed in 1.11.2.

Affected: Go: github.com/dunglas/frankenphp

### Summary

When running FrankenPHP in **worker mode**, the `$_SESSION` superglobal is not correctly reset between requests. This allows a subsequent request processed by the same worker to access the `$_SESSION` data of the previous request (potentially belonging to a different user) before `session_start()` is called.

### Details

In standard PHP execution, the environment is torn down completely after every request. In FrankenPHP's worker mode, the application stays in memory, and superglobals are manually reset between requests.

The vulnerability exists because `$_SESSION` is stored in the Zend Engine's symbol table (`EG(symbol_table)`). While the standard PHP request shutdown (RSHUTDOWN) decrements the reference count of the session data, it does not remove the `$_SESSION` variable itself from the symbol table. FrankenPHP's reset logic (`frankenphp_reset_super_globals`) previously cleared other superglobals but failed to explicitly delete `$_SESSION`.

Consequently, until `session_start()` is called in the new request (which re-initializes the variable), the `$_SESSION` array retains the data from the previous request processed by that specific worker thread.

### Impact

This is a **cross-request data leakage** vulnerability.

* **Confidentiality:** If an application reads `$_SESSION` before calling `session_start()`, it can access sensitive information (authentication tokens, user IDs, PII) belonging to the previous user. * **Logic Errors / Impersonation:** If appl…