medium6.1
CVE-2026-49210
symfony/ux-live-component: XSS via attacker-controlled child component tag
Impact
Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\Util\ChildComponentPartialRenderer::createHtml() interpolates the client-controlled children[id].tag value from LiveComponentSubscriber and InterceptChildComponentRenderSubscriber directly into HTML as a tag name without escaping or validation, allowing arbitrary HTML, including <script> tags, on any Live Component re-render that contains at least one child component. This issue is fixed in versions 2.36.0 and 3.1.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | symfony/ux-live-component | >= 2.8.0, < 2.36.0 | 2.36.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Symfony | Ux | from 2.8.0 before 2.36.0 Version 3.0.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-38x5-rcv4-xf7x
- https://github.com/symfony/ux/security/advisories/GHSA-38x5-rcv4-xf7x
- https://github.com/symfony/ux/commit/fbc5e9a1bda7e4556be21bb1d970f382760ed9a9
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49210.yaml
- https://github.com/symfony/ux/releases/tag/v2.36.0
- https://github.com/symfony/ux/releases/tag/v3.1.0