CVE-2025-47946: symfony ux Cross-site Scripting

Vulnerability summary

CVE-2025-47946 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in symfony ux. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.6% of scored vulnerabilities.

Timeline

1. 19-05-2025
   PublishedVulnerability first disclosed.
2. 20-05-2025
   Last modifiedVulnerability information updated.

Description

Symfony UX is an initiative and set of libraries to integrate JavaScript tools into applications. Prior to version 2.25.1, rendering `{{ attributes }}` or using any method that returns a `ComponentAttributes` instance (e.g. `only()`, `defaults()`, `without()`) ouputs attribute values directly without escaping. If these values are unsafe (e.g. contain user input), this can lead to HTML attribute injection and XSS vulnerabilities. The issue is fixed in version `2.25.1` of `symfony/ux-twig-component` Those who use `symfony/ux-live-component` must also update it to `2.25.1` to benefit from the fix, as it reuses the `ComponentAttributes` class internally. As a workaround, avoid rendering `{{ attributes }}` or derived objects directly if it may contain untrusted values. Instead, use `{{ attributes.render('name') }}` for safe output of individual attributes.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.