GHSA-mm82-c99c-h2cf symfony/ux-live-component: Denial of service via unbounded batch action requests

• Packagist symfony/ux-live-component: >= 2.5.0, < 2.36.0 → fixed in 2.36.0 • Packagist symfony/ux-live-component: >= 3.0.0, < 3.1.0 → fixed in 3.1.0

Description `Symfony\UX\LiveComponent\Controller\BatchActionController::__invoke()` iterates over the client-supplied `actions` array and issues a full `HttpKernel` sub-request for each entry (event subscribers, validators, Doctrine, rendering). The array size is never bounded, so an authenticated client can submit a single `_batch` request containing thousands of actions and exhaust CPU, memory, and database connections on the application server. Resolution `BatchActionController` now enforces an upper bound of 50 actions per `_batch` request (`MAX_ACTIONS_PER_BATCH`) and rejects larger payloads up front with a `BadRequestHttpException`. The matching JavaScript backend was also updated to split larger client-side batches into multiple requests so legitimate usage isn't affected. The patch for this issue is available here for branch 2.x (and forward-ported to 3.x). Credits Symfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.