Vulnerability in Symfony Ux
CVE-2026-49212
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.
EPSS: 0.002 (15.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Symfony Ux — versions >= 3.0.0, < 3.1.0, < 2.36.0, 3.0.0
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-2026-49212?
- CVE-2026-49212 is a high-severity vulnerability in Symfony Ux, classified under Insufficient Verification of Data Authenticity. CVSS score: 7.5/10. Published 2026-07-17.
- How severe is CVE-2026-49212?
- High severity. CVSS v3 base score is 7.5 out of 10.