CVE-2026-49210 json
Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag
published 2026-06-19 4 mo ago modified 2026-10-24 15 d ago also GHSA-38x5-rcv4-xf7x , EUVD-2026-45210
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 27%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- packagist symfony/ux-live-component 2.36.0, 3.1.0
- symfony ux 2.36.0
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 2.3 | 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 |
| CNA | 4.0 | 2.3 | 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 |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | symfony/ux-live-component | >=2.8.0, <2.36.0 >=3.0.0, <3.1.0 |
2.36.0 3.1.0 |
Affected products
- symfony ux
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/symfony/ux/commit/fbc5e9a1bda7e4556be21bb1d970f382760ed9a9
web, patch
-
github.com
/symfony/ux/security/advisories/GHSA-38x5-rcv4-xf7x
web, vendor-advisory
-
github.com
/symfony/ux/releases/tag/v2.36.0
release-notes
-
github.com
/symfony/ux/releases/tag/v3.1.0
release-notes
-
github.com
/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49210.yaml
web
-
github.com
/symfony/ux
package
Sources
- CVE List CVE-2026-49210
- GitHub Advisory GHSA-38x5-rcv4-xf7x
- NVD CVE-2026-49210
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.