{"id":"GHSA-mm82-c99c-h2cf","aliases":["CVE-2026-49209"],"title":"symfony/ux-live-component: Denial of service via unbounded batch action requests","titleSource":"OSV","descriptionSource":"OSV","declaredSeverity":"LOW","description":"### Description\n\n`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.\n\n### Resolution\n\n`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.\n\nThe patch for this issue is available [here](https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f) for branch 2.x (and forward-ported to 3.x).\n\n### Credits\n\nSymfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.","severity":"low","score":1.3,"published":"2026-06-19T19:34:45.000Z","modified":"2026-09-10T03:51:09.083Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Packagist","name":"symfony/ux-live-component","sources":[{"name":"OSV · GHSA-mm82-c99c-h2cf","url":"https://osv.dev/vulnerability/GHSA-mm82-c99c-h2cf"}],"ranges":[{"events":[{"introduced":"2.5.0"},{"fixed":"2.36.0"}],"type":"ECOSYSTEM"}],"versions":["v2.10.0","v2.11.0","v2.11.1","v2.11.2","v2.12.0","v2.13.0","v2.13.1","v2.13.2","v2.13.3","v2.14.0","v2.14.1","v2.14.2","v2.15.0","v2.16.0","v2.17.0","v2.18.0","v2.18.1","v2.19.0","v2.19.2","v2.20.0","v2.21.0","v2.22.0","v2.22.1","v2.23.0","v2.24.0","v2.25.0","v2.25.1","v2.25.2","v2.26.0","v2.26.1","v2.27.0","v2.28.0","v2.28.1","v2.28.2","v2.29.0","v2.29.1","v2.29.2","v2.30.0","v2.31.0","v2.32.0","v2.33.0","v2.34.0","v2.35.0","v2.5.0","v2.6.0","v2.6.1","v2.7.0","v2.7.1","v2.8.0","v2.8.1","v2.9.0","v2.9.1"],"fixed":["2.36.0"]},{"ecosystem":"Packagist","name":"symfony/ux-live-component","sources":[{"name":"OSV · GHSA-mm82-c99c-h2cf","url":"https://osv.dev/vulnerability/GHSA-mm82-c99c-h2cf"}],"ranges":[{"events":[{"introduced":"3.0.0"},{"fixed":"3.1.0"}],"type":"ECOSYSTEM"}],"versions":["v3.0.0"],"fixed":["3.1.0"]}],"sourceAffected":[],"references":["https://github.com/symfony/ux/security/advisories/GHSA-mm82-c99c-h2cf","https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f","https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49209.yaml","https://github.com/symfony/ux"],"sources":[{"name":"OSV","id":"GHSA-mm82-c99c-h2cf","modified":"2026-09-10T03:51:09.083031592Z","url":"https://osv.dev/vulnerability/GHSA-mm82-c99c-h2cf"}],"assessments":[{"source":"OSV","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U","score":1.3}],"products":[],"remediation":[],"kev":{"status":"unavailable","checkedAt":"2026-10-28T21:45:31.439Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}