CVE-2026-118514: medium-severity vulnerability in symfony

In Symfony http-foundation prior to versions 5.4.56, 6.4.50, 7.4.23, and 8.1.11, Symfony\Component\HttpFoundation\RequestMatcher, and RequestMatcher\MethodRequestMatcher which replaces it from 6.2.x on, matches a request against a list of HTTP methods. These compared the request method to the list verbatim, while the router serves a HEAD request with the GET handler, as HTTP semantics require. This came after the incomplete fix of  CVE-2026-45075 https://github.com/advisories/GHSA-6439-2f28-8p8q , which addressed the same gap in the #[IsGranted], #[IsSignatureValid] and #[IsCsrfTokenValid] attributes only. Security rules configured to apply only to GET requests could therefore be bypassed by sending a HEAD request to the same URL. Although HEAD responses contain no body, attackers could still access response headers and trigger the controller's execution, including any side effects. This issue also affects firewalls configured with methods: [GET]. A HEAD request would not match that firewall and could instead be handled by another matching firewall or no firewall at all. Applications using these vulnerable request matchers directly, including through a custom firewall request_matcher, could also be affected. The issue affects symfony/http-foundation through v5.4.55, v6.x through 6.4.49, v7.x through v7.4.22, and v8.x through v8.1.10.