CVE-2025-47946 Symfony UX allows unsanitized HTML attribute injection via ComponentAttributes

What is CVE-2025-47946?

CVE-2025-47946 is a medium-severity cross-site scripting vulnerability in symfony ux, published on 19 May 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official 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.

Weakness: CWE-79

Which versions are affected by CVE-2025-47946?

4 open source packages ship an affected version, including symfony/ux-live-component and symfony/ux-twig-component.

How do I fix CVE-2025-47946?

Upgrade symfony/ux-live-component to 2.25.1 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-47946 being exploited?

There is no known exploitation of CVE-2025-47946 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-5j3w-5pcr-f8hg.