CVE-2026-49210

Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag

Published Jul 17, 2026 CVSS 4.0 · 2.3 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-38x5-rcv4-xf7x symfony/ux-live-component: XSS via attacker-controlled child component tag
History
Type Values Removed Values Added
First Time appeared Symfony
Symfony ux
Vendors & Products Symfony
Symfony ux
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 2.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 17, 2026, 4:52 PM
Reserved
May 28, 2026, 3:42 AM
Status
Analyzed
Published
Jul 17, 2026, 5:17 PM
Modified
Oct 24, 2026, 8:10 PM