CSRF in Symfony Ux
CVE-2026-49215
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.
Vulnerability class: CSRF (Cross-Site Request Forgery)
EPSS: 0.002 (7.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
Affected products
- Symfony Ux — versions >= 3.0.0, < 3.1.0, 3.0.0, >= 2.22.0, < 2.36.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-49215?
- CVE-2026-49215 is a medium-severity vulnerability in Symfony Ux, classified under Cross-Site Request Forgery (CSRF). CVSS score: 5.4/10. Published 2026-07-17.
- How severe is CVE-2026-49215?
- Medium severity. CVSS v3 base score is 5.4 out of 10.