Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Symfony | Ux | >= 2.8.0, < 2.36.0 |
Related Weaknesses (CWE)
References
- https://github.com/symfony/ux/commit/fbc5e9a1bda7e4556be21bb1d970f382760ed9a9Patch
- https://github.com/symfony/ux/releases/tag/v2.36.0Release Notes
- https://github.com/symfony/ux/releases/tag/v3.1.0Release Notes
- https://github.com/symfony/ux/security/advisories/GHSA-38x5-rcv4-xf7xVendor Advisory
FAQ
What is CVE-2026-49210?
CVE-2026-49210 is a vulnerability with a CVSS score of 6.1 (MEDIUM). 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 childr...
How severe is CVE-2026-49210?
CVE-2026-49210 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-49210?
Check the references section above for vendor advisories and patch information. Affected products include: Symfony Ux.