Symfony's incorrect parsing of PATH_INFO can lead to limited authorization bypass

Vulnerability Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Symfony's HttpFoundation component defines an object-oriented layer for the HTTP specification. Starting in version 2.0.0 and prior to version 5.4.50, 6.4.29, and 7.3.7, the `Request` class improperly interprets some `PATH_INFO` in a way that leads to representing some URLs with a path that doesn't start with a `/`. This can allow bypassing some access control rules that are built with this `/`-prefix assumption. Starting in versions 5.4.50, 6.4.29, and 7.3.7, the `Request` class now ensures that URL paths always start with a `/`.

References

• https://github.com/symfony/symfony/security/advisories/GHSA-3rg7-wf37-54rm
• https://github.com/symfony/symfony/commit/9962b91b12bb791322fa73836b350836b6db7cac
• https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/http-foundation/CVE-2025-64500.yaml
• https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2025-64500.yaml
• https://symfony.com/blog/cve-2025-64500-incorrect-parsing-of-path-info-can-lead-to-limited-authorization-bypass