CVE-2026-52821 Kimai: Improper Authorization Through Activity Creation with Preset Project Allows Creation Under Unauthorized Projects
Attackers with basic creation rights can create activities or projects under unauthorized parents, corrupting billing and reporting data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-52821?
CVE-2026-52821 is a medium-severity missing authorization vulnerability in kimai, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Kimai is an open-source time tracking application. Prior to 2.57.0, GET or POST requests to /en/admin/activity/create/{project} and /en/admin/project/create/{customer} require only the generic create_activity or create_project capability and do not verify edit access to the supplied Project or Customer object. A user who knows a valid project.id or customer identifier can use the preset-parent creation logic in src/Controller/ActivityController.php or src/Controller/ProjectController.php to persist a new child business object under an unauthorized parent, polluting project or customer configuration and influencing later time-entry, rate, reporting, and billing behavior. This issue is fixed in version 2.57.0.
Which versions are affected by CVE-2026-52821?
2 open source packages ship an affected version, including kimai/kimai.
| Package | Affected | Fixed in |
|---|---|---|
kimai/kimai Packagist | All versions | 2.57.0 |
kimai/kimai Packagist | All versions | 2.57.0 |
How do I fix CVE-2026-52821?
Upgrade kimai/kimai to 2.57.0 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-52821 being exploited?
There is no known exploitation of CVE-2026-52821 in the wild and no public exploit code.
Sources
Also known as GHSA-3q6q-26vg-v97x.