What’s Vulnerable › Vulnerabilities

CVE-2026-49215: Symfony UX: CSRF Protection Bypass in symfony/ux-live-component — Accept Header is CORS-Safelisted

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-17 · updated 2026-10-24
• Weakness: CWE-352

Description

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; 3.0.0 — fixed in 2.36.0

How to fix

Upgrade to a fixed version: symfony ux 2.36.0. Check the vendor advisory for mitigations.

References

• https://github.com/symfony/ux/commit/aed7493db2b4b7bf1f9c79b33cda544f06904b27
• https://github.com/symfony/ux/releases/tag/v2.36.0
• https://github.com/symfony/ux/releases/tag/v3.1.0
• https://github.com/symfony/ux/security/advisories/GHSA-4m4j-hmqq-3gxm

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