Drupal Core: Unfiltered Error Messages Allow Reflected XSS

Published as "Drupal Core Potential Cross-Site Scripting (XSS) via Error Messages"

medium Drupal · Last reviewed Nov 8, 2026

CVE: CVE-2025-3057
GHSA: GHSA-39g6-x4x8-5jcm
Packagist: PKSA-s1zc-gcfk-ddw5
Reported: Apr 1, 2025

Lets an attacker run script in a visitor's browser on a Drupal site by getting them to open a crafted link.

Affected and fixed versions

In drupal/core. Find the row for the version you run, and update to the release next to it.

If you run	Update to	Support
11.1.0 – 11.1.2	11.1.3
11.0.0 – 11.0.11	11.0.12
10.4.0 – 10.4.2	10.4.3

Show 1 older branch

8.0.0 – 10.3.12

10.3.13

Upgrade

Run the line for the branch you are on.

composer require drupal/core:^11.1.3
composer require drupal/core:^11.0.12
composer require drupal/core:^10.4.3

What this means

Drupal core didn't filter some error messages well enough. An attacker can use this to run their own script in the browser of someone who opens a crafted link to your site. This is reflected cross-site scripting (XSS): the attack lives in the link, not on the site. The script runs with that visitor's session, so it can read or change what they can. See Drupal's advisory.

Who is affected

Every site on an affected version of drupal/core. Drupal says all module configurations are exploitable, and the attacker needs no account. The visitor does have to open the attacker's link. Sites protected by Drupal Steward are already covered, but Drupal still recommends updating.

What to do

Update to the fixed release for your branch:

Drupal 10.3: update to 10.3.13
Drupal 10.4: update to 10.4.3
Drupal 11.0: update to 11.0.12
Drupal 11.1: update to 11.1.3

Drupal 10 releases before 10.3 no longer get security fixes, so move to a supported branch.

Reported by Arne, bdanin, Douglas Groene, Dragos Dumitrescu, Flo Kosiol, Gerardo Cadau, Justin Christoffersen, nuwans, Sven Decabooter and Will Gunn.

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: Drupal Core: Unfiltered Error Messages Allow Reflected XSS (CVE-2025-3057, GHSA-39g6-x4x8-5jcm)
Details: https://phpnews.net/security/drupal/ghsa-39g6-x4x8-5jcm

Affected versions, as Composer constraints:
- drupal/core: >=11.1.0,<11.1.3|>=11.0.0,<11.0.12|>=10.4.0,<10.4.3|>=8.0.0,<10.3.13

Fixed releases:
- 11.1.0 – 11.1.2: update to 11.1.3
- 11.0.0 – 11.0.11: update to 11.0.12
- 10.4.0 – 10.4.2: update to 10.4.3

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/drupal/ghsa-39g6-x4x8-5jcm 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 Drupal advisories