Vulnerability Report

CVE-2026-49210

Title: Symfony UX LiveComponent XSS via Tag Interpolation

XSS

Proof Of Concept

No public PoC currently indexed for CVE-2026-49210.

CWE Category CWE-79
Published Date Jul 17, 2026
Modified Date Jul 20, 2026
Exploit Status Not Found
Score 2.3 CVSS v4.0
Exploit Probability (EPSS)
0.19%

Vulnerability Summary

CVE-2026-49210: 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.

Impacted Vendors

S
symfony 1

Reference Links

https://github.com/symfony/ux/commit/fbc5e9a1bda7e4556be21bb1d970f382760ed9a9 https://github.com/symfony/ux/releases/tag/v2.36.0 https://github.com/symfony/ux/releases/tag/v3.1.0 https://github.com/symfony/ux/security/advisories/GHSA-38x5-rcv4-xf7x
CVSS v4.0
Source Entity [email protected]
Severity LOW
2.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
PASSIVE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.1
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-49210 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction PASSIVE
CVSS Vector String 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected Stack

No specific products linked.