CVE-2026-49210: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in symfony ux
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.
AI Analysis
Technical Summary
Symfony UX versions 2.8.0 through before 2.36.0 and 3.1.0 contain a cross-site scripting vulnerability (CWE-79) in the ChildComponentPartialRenderer::createHtml() function. This function interpolates the client-controlled children[id].tag value directly into HTML as a tag name without escaping or validation. This flaw allows an attacker to inject arbitrary HTML, including <script> tags, during any Live Component re-render that includes at least one child component. The vulnerability is resolved in versions 2.36.0 and 3.1.0.
Potential Impact
An attacker able to influence the children[id].tag value in a Live Component can inject arbitrary HTML or JavaScript code into the rendered page, potentially leading to cross-site scripting attacks. This could result in limited impact such as UI manipulation or script execution in the context of the affected web application. The CVSS 4.0 score is low (2.3), reflecting the requirement for user interaction and the limited scope of the impact.
Mitigation Recommendations
This vulnerability is fixed in Symfony UX versions 2.36.0 and 3.1.0. Users should upgrade to these versions or later to remediate the issue. No official patch or workaround is indicated beyond upgrading. Patch status is not explicitly confirmed in a vendor advisory, so users should verify with the official Symfony UX release notes or security advisories for confirmation.
CVE-2026-49210: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in symfony ux
Description
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.
CVSS v4.0
Score 2.3low
Affected software
pkg:github/symfony/uxRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Symfony UX versions 2.8.0 through before 2.36.0 and 3.1.0 contain a cross-site scripting vulnerability (CWE-79) in the ChildComponentPartialRenderer::createHtml() function. This function interpolates the client-controlled children[id].tag value directly into HTML as a tag name without escaping or validation. This flaw allows an attacker to inject arbitrary HTML, including <script> tags, during any Live Component re-render that includes at least one child component. The vulnerability is resolved in versions 2.36.0 and 3.1.0.
Potential Impact
An attacker able to influence the children[id].tag value in a Live Component can inject arbitrary HTML or JavaScript code into the rendered page, potentially leading to cross-site scripting attacks. This could result in limited impact such as UI manipulation or script execution in the context of the affected web application. The CVSS 4.0 score is low (2.3), reflecting the requirement for user interaction and the limited scope of the impact.
Mitigation Recommendations
This vulnerability is fixed in Symfony UX versions 2.36.0 and 3.1.0. Users should upgrade to these versions or later to remediate the issue. No official patch or workaround is indicated beyond upgrading. Patch status is not explicitly confirmed in a vendor advisory, so users should verify with the official Symfony UX release notes or security advisories for confirmation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-28T03:42:34.340Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a5b5eba2d1edb114c7fb76c
Added to database: 07/18/2026, 11:08:42 UTC
Last enriched: 07/18/2026, 12:02:03 UTC
Last updated: 08/31/2026, 22:52:11 UTC
Views: 59
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