{"id":"GHSA-34w5-c283-j9fg","summary":"symfony/ux-live-component: LiveComponentHydrator HMAC checksum lacks component and slot binding","details":"### Description\n\nIn `symfony/ux-live-component`, a component's server-side state is exposed to the browser as a set of props (`#[LiveProp]`-annotated properties). Props marked `writable: true` can be freely changed by the client. Read-only props are round-tripped to the browser and back, and their integrity is protected by an HMAC so the client cannot tamper with them. Child components additionally receive a `propsFromParent` blob, also HMAC-signed.\n\nThe HMAC computed by `Symfony\\UX\\LiveComponent\\LiveComponentHydrator` covered only the sorted prop key/value pairs. It didn't include the component name, the slot identifier (`props` vs `propsFromParent`), or any request context, and a single application-wide secret is used for every component. A signed blob the server minted for component A is therefore a valid signature for component B if the key names happen to match, and a `props` blob can be replayed in the `propsFromParent` slot (or the reverse). An attacker can use this to set a read-only prop on a target component to a value they were only ever allowed to choose as a writable prop on another component.\n\n### Resolution\n\nThe HMAC is now bound to its context: the component name and a slot identifier are included in the pre-image before hashing. Two constants (`CHECKSUM_SLOT_PROPS` and `CHECKSUM_SLOT_PROPS_FROM_PARENT`) name the two slots, and `calculateChecksum()`, `verifyChecksum()`, `addChecksumToData()`, and `ChildComponentPartialRenderer` thread these values through. Cross-component and cross-slot replays no longer verify.\n\nThe patch for this issue is available [here](https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c) 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-2026-49212"],"modified":"2026-09-10T03:51:07.649941508Z","published":"2026-06-19T19:34:56Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-06-19T19:34:56Z","nvd_published_at":null,"cwe_ids":["CWE-345"],"severity":"LOW"},"references":[{"type":"WEB","url":"https://github.com/symfony/ux/security/advisories/GHSA-34w5-c283-j9fg"},{"type":"WEB","url":"https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49212.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":"2.8.0"},{"fixed":"2.36.0"}]}],"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","v2.8.0","v2.8.1","v2.9.0","v2.9.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-34w5-c283-j9fg/GHSA-34w5-c283-j9fg.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-34w5-c283-j9fg/GHSA-34w5-c283-j9fg.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"}]}