Symfony UX Twig Components: Unescaped Attributes Allow XSS

Published as "symfony/ux-live-component Unsanitized HTML attribute injection via ComponentAttributes"

medium Symfony Symfony UX · Last reviewed Nov 8, 2026

CVE: CVE-2025-47946
GHSA: GHSA-5j3w-5pcr-f8hg
Packagist: PKSA-9bp8-3bj8-8jj2
Reported: May 19, 2025

Lets an attacker inject HTML and script into pages that render component attributes holding user input with {{ attributes }}.

Affected and fixed versions

In 2 packages: symfony/ux-live-component and symfony/ux-twig-component. Find the row for the version you run, and update to the release next to it.

If you run	Update to	Support
Up to 2.25.0	2.25.1	Supported

Upgrade

Run the line for the branch you are on. 1 other package listed above is affected too; update it the same way.

composer require symfony/ux-live-component:^2.25.1

What this means

Symfony UX Twig and Live components printed attribute values without escaping them. If an attribute holds user input, an attacker can inject extra HTML attributes or script into the page (cross-site scripting, or XSS, which runs the attacker's code in a visitor's browser). See the Symfony advisory.

Who is affected

Apps on symfony/ux-twig-component or symfony/ux-live-component before 2.25.1 whose component templates render {{ attributes }}, or the result of only(), defaults() or without(), when any attribute value can come from a user. Components whose attributes only ever hold values you set yourself aren't exposed.

What to do

Update symfony/ux-twig-component to 2.25.1. If you use symfony/ux-live-component, update it to 2.25.1 as well: it reuses the same ComponentAttributes class, so you need both updates to get the fix.

Until you can update, Symfony suggests not rendering {{ attributes }} or the objects derived from it when they may hold untrusted values. Use {{ attributes.render('name') }} to output single attributes safely instead.

Reported by Martin Hložek and Dimitar Raichev.

Check your app with an agent

Paste this into a coding agent that can read your project, such as Claude Code, Codex or Amp. It checks your composer.lock against the versions above and tells you what to update, without changing anything.

Check whether the PHP project you have access to is affected by this security advisory, and tell me what to update. Do a read-only check: don't edit files, don't run composer update or composer require, and don't try to reproduce the flaw.

Advisory: Symfony UX Twig Components: Unescaped Attributes Allow XSS (CVE-2025-47946, GHSA-5j3w-5pcr-f8hg)
Details: https://phpnews.net/security/symfony/ghsa-5j3w-5pcr-f8hg

Affected versions, as Composer constraints:
- symfony/ux-live-component, symfony/ux-twig-component: <2.25.1

Fixed releases on branches that still get security fixes:
- Up to 2.25.0: update to 2.25.1

1. Find every composer.lock in the project outside vendor/ (a monorepo can have one per app) and read the installed version of each package above. Packages installed as dependencies of other packages count too.
2. Compare each installed version with its constraint: "|" separates alternative ranges, and "," means both bounds apply.
3. For each affected install, read "What this means" at https://phpnews.net/security/symfony/ghsa-5j3w-5pcr-f8hg and check whether the project meets the conditions it describes (a feature in use, a config value, a driver) (if that page won't load, use https://github.com/advisories/GHSA-5j3w-5pcr-f8hg). Say which conditions you could check and which you couldn't.
4. Report a table: lock file | package | installed version | affected (yes, no or unknown) | conditions met (yes, no or unknown) | update to | evidence. For each affected package, give the command that would fix it, without running it: composer update <package> --with-dependencies when it is only installed as a dependency of another package, or composer require with the fixed version when composer.json requires it directly. If the installed version is on a branch with no fixed release listed, say it needs a move to a newer branch.

Sources

← All Symfony UX advisories