Drupal Core: Users Can Register With an Email Address Already in Use

Published as "Drupal core Access bypass"

medium Drupal · Last reviewed Nov 9, 2026

CVE: CVE-2024-55634
GHSA: GHSA-7cwc-fjqm-8vh8
Packagist: PKSA-ts55-c66h-g96n
Reported: Dec 10, 2024

Lets a user sign up with an email address another account already has, written in different letter case, on some Drupal database setups.

Affected and fixed versions

In 2 packages: drupal/core and drupal/core-recommended. Find the row for the version you run, and update to the release next to it.

If you run	Update to	Support
11.0.0 – 11.0.7	11.0.8
10.3.0 – 10.3.8	10.3.9
8.0.0 – 10.2.10	10.2.11

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 drupal/core:^11.0.8
composer require drupal/core:^10.3.9
composer require drupal/core:^10.2.11

What this means

A user may be able to register with the same email address as an existing account, by changing the letter case. Drupal's uniqueness check for some user fields behaved differently depending on the database engine and its collation, and Drupal says this can lead to data integrity problems. A collation is the set of rules a database uses to compare text, such as whether A and a count as the same letter.

Who is affected

Sites on drupal/core 8.0.0 and later below 10.2.11, 10.3.0 below 10.3.9, and 11.0.0 below 11.0.8. Whether duplicate addresses get through depends on the database engine and collation in your site's $databases settings. Drupal 7 is not affected.

What to do

Update to the fixed release for your branch: 10.2.11, 10.3.9 or 11.0.8. Drupal 8, Drupal 9 and Drupal 10 before 10.2 no longer get security fixes. See SA-CORE-2024-004 and the fix.

Updating does not repair accounts that already share an address in different case. Drupal's guide Fixing emails that vary only by case covers those.

Reported by Wayne Eaker.

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: Users Can Register With an Email Address Already in Use (CVE-2024-55634, GHSA-7cwc-fjqm-8vh8)
Details: https://phpnews.net/security/drupal/ghsa-7cwc-fjqm-8vh8

Affected versions, as Composer constraints:
- drupal/core, drupal/core-recommended: >=11.0.0,<11.0.8|>=10.3.0,<10.3.9|>=8.0.0,<10.2.11

Fixed releases:
- 11.0.0 – 11.0.7: update to 11.0.8
- 10.3.0 – 10.3.8: update to 10.3.9
- 8.0.0 – 10.2.10: update to 10.2.11

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-7cwc-fjqm-8vh8 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

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