CVE-2026-49212: Symfony Ux

High severity, CVSS 7.5. EPSS: 0.2% chance of exploitation in the next 30 days.

Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, the HMAC computed by Symfony\UX\LiveComponent\LiveComponentHydrator covered only sorted prop key/value pairs and did not include the component name, the slot identifier (props vs propsFromParent), or request context, allowing a signed blob minted for one component or slot to be replayed in another and set a read-only prop on a target component. This issue is fixed in versions 2.36.0 and 3.1.0.

Affected products

• Symfony Ux: from 2.8.0, before 2.36.0 (fixed in 2.36.0); version 3.0.0 only

Published 2026-07-17. Last modified 2026-07-20.