{"id":"GHSA-4m4j-hmqq-3gxm","summary":"symfony/ux-live-component: CSRF Protection Bypass — Accept Header is CORS-Safelisted","details":"### Description\n\nWhen using `symfony/ux-live-component`, methods annotated with `#[LiveAction]` are invokable from the browser and mutate server-side state via AJAX. `Symfony\\UX\\LiveComponent\\EventListener\\LiveComponentSubscriber::isLiveComponentRequest()` gated these invocations on the presence of `Accept: application/vnd.live-component+html`, with a code comment stating that this acted as a CSRF protection.\n\nThe `Accept` header is a [CORS-safelisted request header](https://fetch.spec.whatwg.org/#cors-safelisted-request-header), so a cross-origin `fetch()` can set it without triggering a preflight. The header therefore provided no CSRF protection. Any `#[LiveAction]` could be forged cross-origin against a victim's session.\n\nIn practice the attack is mitigated by `SameSite=Lax` session cookies (Symfony's default), but applications using `SameSite=None`, `credentials: 'include'` with a permissive cookie policy, or that have been pivoted from another same-origin vector remained exposed.\n\n### Resolution\n\n`isLiveComponentRequest()` now additionally requires the request header `X-Requested-With: XMLHttpRequest`. This header is **not** CORS-safelisted, so the browser issues a preflight `OPTIONS` request for any cross-origin attempt; Symfony does not advertise CORS for LiveComponent endpoints, the preflight fails, and the real request is blocked before it reaches the application. The bundled Stimulus client already sends `X-Requested-With` on every LiveComponent request (`RequestBuilder.ts`), so standard usage is unaffected. Cross-origin callers must add `X-Requested-With` to their CORS `Access-Control-Allow-Headers` allow-list.\n\nThe patch for this issue is available [here](https://github.com/symfony/ux/commit/aed7493db2b4b7bf1f9c79b33cda544f06904b27) for branch 2.x (and forward-ported to 3.x).\n\n### Credits\n\nSymfony would like to thank Anthropic (via Project Glasswing) for reporting the issue and Hugo Alliaume for providing the fix.","aliases":["CVE-2026-49215"],"modified":"2026-09-10T03:51:07.830644680Z","published":"2026-06-19T19:35:01Z","database_specific":{"nvd_published_at":null,"cwe_ids":["CWE-352"],"severity":"LOW","github_reviewed":true,"github_reviewed_at":"2026-06-19T19:35:01Z"},"references":[{"type":"WEB","url":"https://github.com/symfony/ux/security/advisories/GHSA-4m4j-hmqq-3gxm"},{"type":"WEB","url":"https://github.com/symfony/ux/commit/aed7493db2b4b7bf1f9c79b33cda544f06904b27"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49215.yaml"},{"type":"PACKAGE","url":"https://github.com/symfony/ux"}],"affected":[{"package":{"name":"symfony/ux-live-component","ecosystem":"Packagist","purl":"pkg:composer/symfony/ux-live-component"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.22.0"},{"fixed":"2.36.0"}]}],"versions":["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"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-4m4j-hmqq-3gxm/GHSA-4m4j-hmqq-3gxm.json"}},{"package":{"name":"symfony/ux-live-component","ecosystem":"Packagist","purl":"pkg:composer/symfony/ux-live-component"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0.0"},{"fixed":"3.1.0"}]}],"versions":["v3.0.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-4m4j-hmqq-3gxm/GHSA-4m4j-hmqq-3gxm.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"}]}