CVE-2026-52822: Kimai/kimai Improper Authorization Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-c6w6-57jj-62vh",
  "modified" : "2026-07-14T00:04:26Z",
  "published" : "2026-07-14T00:04:26Z",
  "aliases" : [ "CVE-2026-52822" ],
  "summary" : "Improper Authorization in Kimai Timesheet Restart and Duplicate Allows New Timesheets After Project Access Revocation",
  "details" : "### Summary\n\nKimai 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.\n\nThis 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.\n\n### Details\n\nThe issue affects the following operations:\n\n- `PATCH /api/timesheets/{id}/restart`\n- `PATCH /api/timesheets/{id}/duplicate`\n\nThe 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.\n\nThe restart/duplicate capability check also verifies only object visibility, not whether the current user still has team-based access to the referenced objects. \n\nIn `src/API/TimesheetController.php`, the restart flow copies the historical `project` and `activity` into a new candidate timesheet.\n\nThe duplicate flow similarly clones the historical record and saves it.\n\nIn `src/Timesheet/TimesheetService.php`, creation of a new running entry still relies on `isGranted('start', $timesheet)`.\n\nFor 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to the current user, this logic can still succeed through the `*_own_timesheet` branch even after project access has been revoked.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.\n\nThe same weakness also affects the Web duplicate flow because the UI path ultimately calls the same save logic in `src/Controller/TimesheetAbstractController.php`:\n\n*A PoC was provided, but removed for security reasons.*\n\n### Impact\n\nThis 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.\n\nBecause 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.\n\n# Solution\n\nThe 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.\n\nSee [https://www.kimai.org/en/security/ghsa-c6w6-57jj-62vh](https://www.kimai.org/en/security/ghsa-c6w6-57jj-62vh) for more information.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "kimai/kimai"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.58.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.57.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/kimai/kimai/security/advisories/GHSA-c6w6-57jj-62vh"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/kimai/kimai"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-285", "CWE-862" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-14T00:04:26Z",
    "nvd_published_at" : null
  }
}