Summary
Kimai: Login CSRF in the Timesheet Stop and Restart API Endpoints Allows Unauthorized State Changes
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}/stopGET /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.
A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones. Typical impact: state-changing actions performed as the victim without their consent.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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.
Frequently Asked Questions
- What is CVE-2026-52823? CVE-2026-52823 is a medium-severity cross-site request forgery (CSRF) vulnerability in kimai/kimai (composer), affecting versions <= 2.57.0. It is fixed in 2.58.0. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.
- Which versions of kimai/kimai are affected by CVE-2026-52823? kimai/kimai (composer) versions <= 2.57.0 is affected.
- Is there a fix for CVE-2026-52823? Yes. CVE-2026-52823 is fixed in 2.58.0. Upgrade to this version or later.
- Is CVE-2026-52823 exploitable, and should I be worried? Whether CVE-2026-52823 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-52823 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-52823? Upgrade
kimai/kimaito 2.58.0 or later.