Package Instance

Insufficient Session Expiration
The `PDOSessionHandler` class allows storing sessions on a PDO connection. Under some configurations and with a well-crafted payload, it was possible to do a denial of service on a Symfony application without too much resources.

SQL Injection
In Symfony HTTP Methods provided as verbs or using the override header may be treated as trusted input, but they are not validated, possibly causing SQL injection or XSS.

Symfony vulnerable to command execution hijack on Windows with Process class
### Description

On Windows, when an executable file named `cmd.exe` is located in the current working directory it will be called by the `Process` class when preparing command arguments, leading to possible hijacking.

### Resolution

The `Process` class now uses the absolute path to `cmd.exe`.

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/18ecd03eda3917fdf901a48e72518f911c64a1c9) for branch 5.4.

### Credits

We would like to thank Jordi Boggiano for reporting the issue and Nicolas Grekas for providing the fix.

Cross-Site Request Forgery (CSRF)
By default, a user's session is invalidated when the user is logged out. This behavior can be disabled through the `invalidate_session` option. In this case, CSRF tokens were not erased during logout which allowed for CSRF token fixation.

Cross-site Scripting
In Symfony, validation messages are not escaped, which can lead to XSS when user input is included.