Symfony UX Toolkit: Malicious Kit Can Read and Write Any File

Published as "symfony/ux-toolkit Path Traversal allows arbitrary file write and read via crafted recipe manifest"

high Symfony Symfony UX · Last reviewed Nov 4, 2026

CVE: CVE-2026-55878
GHSA: GHSA-p9xj-fpr2-jf2q
Packagist: PKSA-hmn2-9g3k-g9mr
Reported: Jun 19, 2026

Lets a crafted or compromised recipe kit read or overwrite files outside the project when you run ux:install, which can lead to running code.

Affected and fixed versions

In symfony/ux-toolkit. Find the row for the version you run, and update to the release next to it.

If you run	Update to	Support
3.0.0 – 3.1.x	3.2.0	Supported
2.32.0 – 2.36.0	2.36.1	Supported

Upgrade

Run the line for the branch you are on.

composer require symfony/ux-toolkit:^3.2.0
composer require symfony/ux-toolkit:^2.36.1

What this means

A crafted or compromised recipe kit can make ux:install read or write files outside your project. It can overwrite files like controllers, git hooks or .env on your machine or CI runner, which can lead to running the attacker's code. It can also read files outside the kit's folder.

Who is affected

Projects with symfony/ux-toolkit from 2.32.0 up to (not including) 2.36.1, or 3.x before 3.2.0, that run the ux:install console command with a kit you don't fully trust. The Symfony UX advisory says the kit's copy-files map could point outside the intended folder. Files can be overwritten without asking when you pass --force or run non-interactively, as in CI. If you never run ux:install, or only with kits you trust, you aren't exposed.

What to do

Update symfony/ux-toolkit to 3.2.0, or to 2.36.1 on 2.x. The fix rejects any copy-files path that tries to leave its folder, and checks the final path again before each read and write.

Reported by Pascal Cescon.

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 Toolkit: Malicious Kit Can Read and Write Any File (CVE-2026-55878, GHSA-p9xj-fpr2-jf2q)
Details: https://phpnews.net/security/symfony/ghsa-p9xj-fpr2-jf2q

Affected versions, as Composer constraints:
- symfony/ux-toolkit: >=2.32.0,<2.36.1|>=3.0.0,<3.2.0

Fixed releases on branches that still get security fixes:
- 3.0.0 – 3.1.x: update to 3.2.0
- 2.32.0 – 2.36.0: update to 2.36.1

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-p9xj-fpr2-jf2q and check whether the project meets the conditions it describes (a feature in use, a config value, a driver). 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