# CVE-2026-52820: Kimai: Timesheet PATCH/POST allows assigning to project outside user's team via query_builder OR-bypass

> Authenticated users can bypass team access controls to assign timesheets to unauthorized projects and read associated metadata.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-vrr2-g9gh-c3jc

## What is CVE-2026-52820?

CVE-2026-52820 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, PATCH /api/timesheets/{id} and POST /api/timesheets accept a user-controlled project identifier through TimesheetApiEditForm and FormTrait, and ProjectRepository::getQueryBuilderForFormType() places that identifier in an unconditional OR branch that bypasses the team access criteria. Any authenticated user with edit_own_timesheet can therefore assign an owned timesheet to a project outside the user's teams, persist unauthorized project attribution, and retrieve project and customer metadata through GET /api/timesheets/{id}?full=true. TimesheetTeamAccessValidator now checks changed project and activity associations against current team access. This issue is fixed in version 2.57.0.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-52820?

2 open source packages ship an affected version, including kimai/kimai.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `kimai/kimai` | Packagist | All versions | 2.57.0 |
| `kimai/kimai` | Packagist | All versions | 2.57.0 |

## How do I fix CVE-2026-52820?

Upgrade kimai/kimai to 2.57.0 or later.

## Is CVE-2026-52820 being exploited?

There is no known exploitation of CVE-2026-52820 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52820 and fix it if it is affected.

What it is: CVE-2026-52820 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.
Exploitation: There is no known exploitation of CVE-2026-52820 in the wild and no public exploit code.

Affected packages and fixed versions:
- kimai/kimai (Packagist): affected all versions; fixed in 2.57.0
- kimai/kimai (Packagist): affected all versions; fixed in 2.57.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-52820/ (Markdown: https://insights.sbomify.com/CVE-2026-52820/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52820
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52820
- OSV: https://osv.dev/vulnerability/CVE-2026-52820

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52820/
Summaries are generated and may contain mistakes; the official description above is the record.