CVE-2026-52826: Kimai Improper Authorization Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2xgg-2x8h-8xw4",
  "modified" : "2026-07-14T00:09:35Z",
  "published" : "2026-07-14T00:09:35Z",
  "aliases" : [ "CVE-2026-52826" ],
  "summary" : "Kimai: Improper Authorization in Project, Customer, and Activity Rate Edit Endpoints Allows Cross-Scope Rate Manipulation",
  "details" : "### Summary\n\nKimai 2.56.0 contains an authenticated improper authorization vulnerability in the Web rate editing flows for projects, customers, and activities. A user who can edit one authorized parent object can combine that authorized parent ID with the rate ID of a different, unauthorized parent object and thereby modify the unauthorized rate record.\n\nThis affects `ProjectRate`, `CustomerRate`, and `ActivityRate` editing. The issue is caused by missing parent-child consistency validation and allows cross-project, cross-customer, or cross-activity tampering of billing-related configuration.\n\n### Details\n\nThe issue affects the following Web routes:\n\n- `GET/POST /en/admin/project/{id}/rate/{rate}`\n- `GET/POST /en/admin/customer/{id}/rate/{rate}`\n- `GET/POST /en/admin/activity/{id}/rate/{rate}`\n\nIn both cases, the parent object and the rate object are resolved independently from user-controlled route parameters. The controller only checks whether the current user may edit the parent object referenced by `{id}`, but it does not verify that the child rate object referenced by `{rate}` actually belongs to that same parent.\n\nIn these controllers, there is no validation such as:\n\n- `$rate->getProject() === $project`\n- `$rate->getCustomer() === $customer`\n- `$rate->getActivity() === $activity`\n\nThis missing binding check is especially notable because the API delete endpoints already enforce the expected parent-child relationship.\n\nThis shows that parent-child consistency is already a recognized invariant in the application design, but the Web edit endpoints fail to enforce it for projects, customers, and activities.\n\n*A PoC was provided, but removed for security reasons.*\n\n### Impact\n\nThis vulnerability allows authenticated users to tamper with billing-related rate configuration outside their authorized project, customer, or activity scope. An attacker can modify rate values belonging to other teams or business domains, which can affect time-based settlement, inherited pricing, cost calculations, budget reporting, revenue reporting, and downstream invoice generation.\n\nBecause the issue directly persists changes into `kimai2_projects_rates`, `kimai2_customers_rates`, and `kimai2_activities_rates`, it is a real cross-scope integrity vulnerability rather than a UI-only flaw. The attack breaks team-based isolation boundaries for high-value financial configuration.\n\n# Solution\n\nThe rate edit forms for `customers`, `projects` and `activities` now verify that the rate belongs to the parent referenced in the URL and reject the request otherwise.\n\nSee [https://www.kimai.org/en/security/ghsa-2xgg-2x8h-8xw4](https://www.kimai.org/en/security/ghsa-2xgg-2x8h-8xw4) 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" : "2.57.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.56.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/kimai/kimai/security/advisories/GHSA-2xgg-2x8h-8xw4"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/kimai/kimai"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-285", "CWE-639" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-14T00:09:35Z",
    "nvd_published_at" : null
  }
}