Is CVE-2026-52821 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-52821 being exploited in the wild.

How severe is CVE-2026-52821?

Medium severity, with a CVSS score of 4, published 15 September 2026.

Which products and versions are affected?

Kimai <= 2.56.0; kimai/kimai (Packagist) <= 2.56.0, ECOSYSTEM:introduced=0,fixed=2.57.0.

Is there a fix for CVE-2026-52821?

Yes. kimai/kimai (Packagist): upgrade to 2.57.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-52821 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-52821?

Check whether you run Kimai or kimai/kimai (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-52821: Kimai improper authorization in activity and project creation

Q: Which products and versions are affected?

Kimai <= 2.56.0; kimai/kimai (Packagist) <= 2.56.0, ECOSYSTEM:introduced=0,fixed=2.57.0.

Q: Is there a fix for CVE-2026-52821?

Yes. kimai/kimai (Packagist): upgrade to 2.57.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-52821 attacked?

It is attacked over the network, in a network appliance.

Q: Am I affected by CVE-2026-52821?

Check whether you run Kimai or kimai/kimai (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-52821 · Severity: medium · CVSS 4 · Published 2026-09-15

Kimai, an open-source time-tracking application, contains a flaw that allows users to create activities or projects under categories they are not authorized to access. An authenticated user could exploit this to inject data into other teams' projects, potentially disrupting project management, billing rates, and reporting. This could lead to data pollution and business process errors across different departments or clients.

Technologies: Kimai, kimai/kimai (Packagist). Vendors: Kimai, Packagist.

Quick answers

Is CVE-2026-52821 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-52821 being exploited in the wild.
How severe is CVE-2026-52821?: Medium severity, with a CVSS score of 4, published 15 September 2026.
Which products and versions are affected?: Kimai <= 2.56.0; kimai/kimai (Packagist) <= 2.56.0, ECOSYSTEM:introduced=0,fixed=2.57.0.
Is there a fix for CVE-2026-52821?: Yes. kimai/kimai (Packagist): upgrade to 2.57.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-52821 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-52821?: Check whether you run Kimai or kimai/kimai (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

kimai/kimai (Packagist): upgrade to 2.57.0 or later
```
composer require kimai/kimai:^2.57.0
```

Technical details

An improper authorization vulnerability exists in Kimai's ActivityController and ProjectController. The application fails to verify if an authenticated user has the necessary permissions to associate a new activity with a specific project, or a new project with a specific customer, when using preset identifiers in the URL (e.g., /en/admin/activity/create/{project}). An attacker with basic 'create_activity' permissions can bypass project-level access controls by supplying a valid project ID they do not own. This allows for persistent cross-project object injection. The issue is resolved in version 2.57.0 by implementing 'IsGranted' checks for the parent objects during the creation flow.

Affected products

Kimai Kimai <= 2.56.0

Identifiers

CVE-2026-52821
GHSA-3q6q-26vg-v97x

Timeline

2026-06-11: disclosed: Initial disclosure by reporter
2026-07-14: advisory: GitHub Advisory published
2026-07-14: patched: Fix released in version 2.57.0

References

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