GHSA-c6w6-57jj-62vh CVE-2026-52822
Improper Authorization in Kimai Timesheet Restart and Duplicate Allows New Timesheets After Project Access Revocation
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.46%
- Chance of exploitation in the next 30 days. Higher than 40.28% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
2.58.0- Upgrade kimai/kimai to this version or later
Description
Summary
Kimai 2.56.0 contains an authenticated authorization bypass in the timesheet restart and duplicate workflows. After a user loses access to a project, the user can still derive a new timesheet from one of their historical entries and create a new record under that now-unauthorized project and activity combination.
This is a permission revocation bypass with persistent write impact. The issue affects both restart and duplicate, which trust ownership of an old timesheet more than the user's current access to the underlying project, activity, and customer.
Details
The issue affects the following operations:
PATCH /api/timesheets/{id}/restartPATCH /api/timesheets/{id}/duplicate
The root cause is that authorization gives too much weight to the fact that the original timesheet belongs to the current user. In src/Voter/TimesheetVoter.php, the *_own_timesheet branch is evaluated before team-based access checks.
The restart/duplicate capability check also verifies only object visibility, not whether the current user still has team-based access to the referenced objects.
In src/API/TimesheetController.php, the restart flow copies the historical project and activity into a new candidate timesheet.
The duplicate flow similarly clones the historical record and saves it.
In src/Timesheet/TimesheetService.php, creation of a new running entry still relies on isGranted('start', $timesheet).
For historical entries that belong to the current user, this logic can still succeed through the *_own_timesheet branch even after project access has been revoked. As a result, normal creation pages correctly stop offering the revoked project, but restart and duplicate can still create new records under it.
The same weakness also affects the Web duplicate flow because the UI path ultimately calls the same save logic in src/Controller/TimesheetAbstractController.php:
A PoC was provided, but removed for security reasons.
Impact
This vulnerability allows a user to keep writing new time entries into a project after project access has been revoked. That undermines administrative access-control changes and can pollute project time tracking, budget calculations, statistics, reports, and invoicing workflows.
Because both restart and duplicate can reuse historical project/activity bindings, old timesheet records effectively become reusable capability tokens that survive later access-control changes. This is not a UI artifact or a caching problem: new database rows are persisted after revocation.
Solution
The metoid TimesheetVoter::canStart() now checks team access for project and activity. This verification is used for new timesheets and also for the duplication and restart workflows.
See https://www.kimai.org/en/security/ghsa-c6w6-57jj-62vh for more information.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| kimai/kimai | < 2.58.0 |
2.58.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
kimai/kimai Packagist → 2.58.0
- composer
composer require kimai/kimai:^2.58.0
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- Low
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-285: Improper Authorization
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that you perform access control checks related to your business logic. These checks may be different than the access control checks that you apply to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
CWE-862: Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-rw46-qg69-vg6h Kimai: ExportTemplate CRUD Missing Authorization Check Allows Unauthorized TEAMLEAD Access | Medium | Also affects kimai/kimai |
| GHSA-v8hx-4vx8-wc96 Kimai: Pre-2FA KIMAI_SESSION cookie grants full authenticated REST API access, bypassing TOTP | High | Also affects kimai/kimai |
| GHSA-2xgg-2x8h-8xw4 Kimai: Improper Authorization in Project, Customer, and Activity Rate Edit Endpoints Allows Cross-Scope Rate Manipulation | Medium | Also affects kimai/kimai |
| GHSA-xv4r-4885-gwpg Kimai has Improper Authorization in Team Member and Team Activity Assignment APIs Which Allows Expansion of Team Scope Beyond Authorized Visibility | Medium | Also affects kimai/kimai |
| GHSA-jr9p-4h4j-6c58 Kimai: Default APP_SECRET in Docker Image Enables Cookie Forgery and Account Takeover | Critical | Also affects kimai/kimai |
| GHSA-r8vr-m544-qh4h Kimai: Login CSRF in the Timesheet Stop and Restart API Endpoints Allows Unauthorized State Changes | Medium | Also affects kimai/kimai |
| GHSA-3q6q-26vg-v97x Kimai: Improper Authorization Through Activity Creation with Preset Project Allows Creation Under Unauthorized Projects | Medium | Also affects kimai/kimai |
| GHSA-vrr2-g9gh-c3jc Kimai: Timesheet PATCH/POST allows assigning to project outside user's team via query_builder OR-bypass | Medium | Also affects kimai/kimai |
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