CVE-2026-49210
Published:July 17, 2026
Updated:July 21, 2026
Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\Util\ChildComponentPartialRenderer::createHtml() interpolates the client-controlled children[id].tag value from LiveComponentSubscriber and InterceptChildComponentRenderSubscriber directly into HTML as a tag name without escaping or validation, allowing arbitrary HTML, including <script> tags, on any Live Component re-render that contains at least one child component. This issue is fixed in versions 2.36.0 and 3.1.0.
Affected Packages
https://github.com/symfony/ux.git (GITHUB):
Affected version(s) >=v1.0.0 <v2.36.0Fix Suggestion:
Update to version v2.36.0symfony/ux-live-component (PHP):
Affected version(s) =v3.0.0 <v3.1.0Fix Suggestion:
Update to version v3.1.0symfony/ux-live-component (PHP):
Affected version(s) >=v2.8.0 <v2.36.0Fix Suggestion:
Update to version v2.36.0Related Resources (6)
Do you need more information?
Contact UsCVSS v4
Base Score:
2.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
LOW
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.1
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
EPSS
Base Score:
0.19