CVE-2026-52823

Kimai is an open-source time tracking application. Prior to 2.58.0, TimesheetController exposes GET /api/timesheets/{id}/stop and GET /api/timesheets/{id}/restart, which reuse an authenticated browser session and perform state-changing operations through GET requests without a request-forgery defense. A remote attacker can cause a logged-in user to request either route from attacker-controlled content, stopping a running timesheet or restarting a historical entry to create and start a new timesheet without the user's consent. The unauthorized changes can corrupt time records, billing, reports, approvals, and audits. This issue is fixed in version 2.58.0.

Kimai is an open-source time tracking application. Prior to 2.58.0, TimesheetController exposes GET /api/timesheets/{id}/stop and GET /api/timesheets/{id}/restart, which reuse an authenticated browser session and perform state-changing operations through GET requests without a request-forgery defense. A remote attacker can cause a logged-in user to request either route from attacker-controlled content, stopping a running timesheet or restarting a historical entry to create and start a new timesheet without the user's consent. The unauthorized changes can corrupt time records, billing, reports, approvals, and audits. This issue is fixed in version 2.58.0.

Summary

Kimai 2.56.0 contains authenticated cross-site request forgery issues in its timesheet state-changing API endpoints. The application reuses the browser's existing session for /api/* requests, and both the stop and restart operations are exposed through GET and PATCH routes that directly modify business state.

As a result, an attacker can trick a logged-in user into visiting a malicious page and cause unauthorized timesheet actions without the victim's consent. Depending on the endpoint, this can stop a running timesheet or create and start a new one from historical data.

Details

The issue affects at least the following API routes:

• GET /api/timesheets/{id}/stop
• GET /api/timesheets/{id}/restart

Both routes are non-read-only operations but are still exposed as GET. In src/API/TimesheetController.php.

A PoC was provided, but removed for security reasons.

Impact

This vulnerability allows an attacker to trigger unauthorized business-state changes as a logged-in victim. In the validated stop case, a running timesheet can be stopped, affecting time tracking integrity and potentially availability of ongoing work tracking. In the restart case, a historical timesheet can be restarted and a new record can be created without the victim's knowledge.

These actions can corrupt time records, distort billing and reporting, interfere with approvals or audits, and create persistent database-side side effects. Because exploitation requires only that the victim visit a malicious page while authenticated, the attack barrier is low.

Solution

The GET routes were removed, both stop and restart are only available via PATCH.

See https://www.kimai.org/en/security/ghsa-r8vr-m544-qh4h for more information.

Kimai is an open-source time tracking application. Prior to 2.58.0, TimesheetController exposes GET /api/timesheets/{id}/stop and GET /api/timesheets/{id}/restart, which reuse an authenticated browser session and perform state-changing operations through GET requests without a request-forgery defense. A remote attacker can cause a logged-in user to request either route from attacker-controlled content, stopping a running timesheet or restarting a historical entry to create and start a new timesheet without the user's consent. The unauthorized changes can corrupt time records, billing, reports, approvals, and audits. This issue is fixed in version 2.58.0.

Kimai is an open-source time tracking application. Prior to 2.58.0, TimesheetController exposes GET /api/timesheets/{id}/stop and GET /api/timesheets/{id}/restart, which reuse an authenticated browser session and perform state-changing operations through GET requests without a request-forgery defense. A remote attacker can cause a logged-in user to request either route from attacker-controlled content, stopping a running timesheet or restarting a historical entry to create and start a new timesheet without the user's consent. The unauthorized changes can corrupt time records, billing, reports, approvals, and audits. This issue is fixed in version 2.58.0.

Summary

Kimai 2.56.0 contains authenticated cross-site request forgery issues in its timesheet state-changing API endpoints. The application reuses the browser's existing session for /api/* requests, and both the stop and restart operations are exposed through GET and PATCH routes that directly modify business state.

As a result, an attacker can trick a logged-in user into visiting a malicious page and cause unauthorized timesheet actions without the victim's consent. Depending on the endpoint, this can stop a running timesheet or create and start a new one from historical data.

Details

The issue affects at least the following API routes:

• GET /api/timesheets/{id}/stop
• GET /api/timesheets/{id}/restart

Both routes are non-read-only operations but are still exposed as GET. In src/API/TimesheetController.php.

A PoC was provided, but removed for security reasons.

Impact

This vulnerability allows an attacker to trigger unauthorized business-state changes as a logged-in victim. In the validated stop case, a running timesheet can be stopped, affecting time tracking integrity and potentially availability of ongoing work tracking. In the restart case, a historical timesheet can be restarted and a new record can be created without the victim's knowledge.

These actions can corrupt time records, distort billing and reporting, interfere with approvals or audits, and create persistent database-side side effects. Because exploitation requires only that the victim visit a malicious page while authenticated, the attack barrier is low.

Solution

The GET routes were removed, both stop and restart are only available via PATCH.

See https://www.kimai.org/en/security/ghsa-r8vr-m544-qh4h for more information.