CVE-2026-49215: Symfony Ux

Medium severity, CVSS 5.4. EPSS: 0.2% chance of exploitation in the next 30 days.

Symfony UX is a JavaScript ecosystem for Symfony. From 2.22.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\EventListener\LiveComponentSubscriber::isLiveComponentRequest() gates #[LiveAction] invocations on Accept: application/vnd.live-component+html, but the Accept header is CORS-safelisted and cross-origin fetch() can set it without preflight, allowing forged cross-origin #[LiveAction] requests against a victim session when applications use SameSite=None, credentials: 'include', a permissive cookie policy, or a same-origin pivot. This issue is fixed in versions 2.36.0 and 3.1.0.

Affected products

• Symfony Ux: from 2.22.0, before 2.36.0 (fixed in 2.36.0); version 3.0.0 only

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