GHSA-J5MC-P8QG-39J7

Vulnerability from github – Published: 2026-07-02 20:44 – Updated: 2026-07-02 20:44
VLAI
Summary
Kimai Favorite Timesheet Add and Remove Endpoints Allows Cross-User Bookmark Manipulation
Details

Summary

Kimai 2.56.0 contains an authenticated improper authorization / IDOR vulnerability in the favorite timesheet add and remove endpoints. A low-privileged user who knows another user's timesheet.id can add that record to, or remove it from, the victim's favorite/recent bookmark list. This allows cross-user manipulation of per-user favorite state without administrative privileges.

Details

The issue affects the following routes:

  • GET /en/favorite/timesheet/add/{id}
  • GET /en/favorite/timesheet/remove/{id}

Both endpoints accept a user-controlled timesheet identifier and only require the caller to hold the generic start_own_timesheet permission. They do not verify that the referenced Timesheet object belongs to the currently authenticated user.

  • In src/Controller/FavoriteController.php, the controller methods accept a Timesheet object directly and forward it to the favorite service.
  • The root cause becomes more obvious in src/Timesheet/FavoriteRecordService.php. The bookmark owner is derived from $timesheet->getUser() instead of the current session user.
  • Because of this design, any authenticated user who can reference another user's timesheet ID can modify the victim's favorite/recent bookmark data.

A PoC was provided, but removed for security reasons.

Impact

This vulnerability allows any authenticated low-privileged user to manipulate another user's favorite bookmark state across accounts. An attacker can inject arbitrary victim-owned timesheet entries into the victim's quick-entry workflow, remove existing favorites, and repeatedly disturb the victim's normal timesheet usage without needing administrative privileges.

The issue does not directly disclose sensitive data, but it is a real cross-user business-state tampering vulnerability with clear integrity impact. Because the add and remove endpoints can be combined, an attacker can reliably insert, remove, and reorder entries in another user's favorite/recent list.

Severity
1.3 (Low)
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/E:U
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.56.0"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "kimai/kimai"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.57.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-639",
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-02T20:44:05Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\n\nKimai 2.56.0 contains an authenticated improper authorization / IDOR vulnerability in the favorite timesheet add and remove endpoints. A low-privileged user who knows another user\u0027s `timesheet.id` can add that record to, or remove it from, the victim\u0027s `favorite/recent` bookmark list. This allows cross-user manipulation of per-user favorite state without administrative privileges.\n\n### Details\n\nThe issue affects the following routes:\n\n- `GET /en/favorite/timesheet/add/{id}`\n- `GET /en/favorite/timesheet/remove/{id}`\n\nBoth endpoints accept a user-controlled timesheet identifier and only require the caller to hold the generic `start_own_timesheet` permission. They do not verify that the referenced `Timesheet` object belongs to the currently authenticated user.\n\n- In `src/Controller/FavoriteController.php`, the controller methods accept a `Timesheet` object directly and forward it to the favorite service. \n- The root cause becomes more obvious in `src/Timesheet/FavoriteRecordService.php`. The bookmark owner is derived from `$timesheet-\u003egetUser()` instead of the current session user.\n- Because of this design, any authenticated user who can reference another user\u0027s timesheet ID can modify the victim\u0027s `favorite/recent` bookmark data.\n\n*A PoC was provided, but removed for security reasons.*\n\n### Impact\n\nThis vulnerability allows any authenticated low-privileged user to manipulate another user\u0027s favorite bookmark state across accounts. An attacker can inject arbitrary victim-owned timesheet entries into the victim\u0027s quick-entry workflow, remove existing favorites, and repeatedly disturb the victim\u0027s normal timesheet usage without needing administrative privileges.\n\nThe issue does not directly disclose sensitive data, but it is a real cross-user business-state tampering vulnerability with clear integrity impact. Because the add and remove endpoints can be combined, an attacker can reliably insert, remove, and reorder entries in another user\u0027s `favorite/recent` list.",
  "id": "GHSA-j5mc-p8qg-39j7",
  "modified": "2026-07-02T20:44:05Z",
  "published": "2026-07-02T20:44:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/kimai/kimai/security/advisories/GHSA-j5mc-p8qg-39j7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/kimai/kimai"
    },
    {
      "type": "WEB",
      "url": "https://www.kimai.org/en/security/ghsa-j5mc-p8qg-39j7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "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/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Kimai Favorite Timesheet Add and Remove Endpoints Allows Cross-User Bookmark Manipulation"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.