EUVD-2026-78163

Summary

A bug in how ZITADEL updates permissions when multiple project roles are deleted at the same time can cause some user permissions to be missed. This issue specifically affects User Grants on Granted Projects (projects shared between different organizations), potentially allowing users to keep access rights that were supposed to be completely removed.

Impact

When an organization shares a project with another organization (a Project Grant), administrators can assign specific roles to users via a User Grant. If multiple roles are deleted from that project at the same time, a background process runs to strip those roles from the assigned users.

Because of an error in how ZITADEL loops through a user's list of roles during this specific cross-organization cleanup, deleting two or more roles at once might cause the system to accidentally skip over some of them.

> Scope Note: This vulnerability only affects User Grants on Granted Projects. Direct project roles and global organization roles are not impacted.

The risk depends entirely on what the skipped role allowed the user to do-if it was an administrative or high-privilege role, the user could potentially retain those elevated permissions within that granted project even after the role was officially deleted.

Affected Versions

• 4.x: 4.0.0 through 4.15.3 (including RC versions)
• 3.x: 3.0.0 through 3.4.12 (including RC versions)

Note: The 3.x release channel has reached End-of-Life (EOL) for security updates and will not receive a backported patch.

Patches & Resolution

This issue has been fully resolved in the latest releases.

The update fixes the role-removal logic to ensure no roles are skipped. Furthermore, this patch includes an automatic database migration. When you update, the system will automatically scan your database, find any user permissions on granted projects that may have been accidentally left behind by this bug, and correct them.

• 4.x: Upgrade to $\ge$4.16.0
• 3.x: Update to $\ge$4.16.0 (or check out workarounds)

Workarounds

There are no configuration workarounds. Upgrading to a patched version is the recommended solution and only way to trigger the automatic cleanup migration. If you cannot upgrade immediately, we recommend manually reviewing user permissions specifically for your Granted Projects where multiple roles were recently deleted.

Questions

If you have any questions or comments about this advisory, please reach out to us at security@zitadel.com.

Credits

Thanks to AyushParkara for reporting this vulnerability.