CVE-2026-59222: Open WebUI /api/v1/channels/{id}/members Exposes Full User Model Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-gh7p-78x6-jw6m",
  "modified" : "2026-07-24T17:04:55Z",
  "published" : "2026-07-24T17:04:55Z",
  "aliases" : [ "CVE-2026-59222" ],
  "summary" : "Open WebUI: /api/v1/channels/{id}/members exposes full user model including sensitive credentials",
  "details" : "### Summary\n\nThe channel members endpoint serializes and returns **full user models** for channel participants, including settings objects. A normal user in a DM can retrieve admin-only sensitive configuration such as webhook URLs and tool server key material (`settings.ui.toolServers[].key`), which is not available via standard user info APIs.\n\n### Details\n\nThe endpoint GET `/api/v1/channels/{id}/members` returns the full serialized user model for every member in the channel. In both the DM and non-DM code paths, the handler constructs the response with `[UserModelResponse(**user.model_dump(), is_active=...)]` and returns it as the users list. Because `UserModel` (`models/users.py`) includes a settings object (`UserSettings`) and arbitrary UI configuration (`settings.ui`), the endpoint exposes other users' sensitive configuration to any channel participant.\n\nPractically, a regular user who participates in a DM or group can call `/api/v1/channels/{id}/members` and receive other members' settings, including admin-only details such as webhook notification URLs and tool server configuration, including credential fields like `settings.ui.toolServers[].key`. These values are not returned by the normal user profile endpoints (e.g., `/api/v1/users/{user_id}/info`).\n\n### PoC\n\n1. Start a local Open WebUI instance\n2. Log in as admin and in the Admin Panel, go to Settings -> General and check *Channels (Beta)*, then press Save.\n3. Create a low-privilege user in the Users tab\n4. Click on the admin's profile bottom left, Settings and Integrations. Then click the `+` after *Manage Tool Servers* to add some tool server with a secret Bearer token (eg. `KEY`)\n5. Log in as the attacker with the low-privilege account and create a new Direct Message channel with the admin user:\n\n<img width=\"690\" height=\"383\" alt=\"image\" src=\"https://github.com/user-attachments/assets/70208661-a0db-4457-9984-119056ca3daf\" />\n\n7. After creating, open DevTools with F12 and go to the Network tab. Then in the DM UI click on the *Users* icon top right to see the members. In the network tab, this should have triggered a `/api/v1/channels/{id}/members` request which responds with the `settings` key including `toolServers` and `key` values:\n\n<img width=\"1642\" height=\"577\" alt=\"image\" src=\"https://github.com/user-attachments/assets/6639d982-a156-4e8b-861e-587d86d9b152\" />\n\nThe attacker has now leaked the admin's bearer token for the toolserver they configured.\n\n### Impact\n\nConditions for exploit: channels are enabled and an attacker has a low-privilege account.\n\nWebhook URLs and tool server configurations (including bearer keys) can be exfiltrated from any user.\n\n### Original Agent Report\n\n<img width=\"400\" alt=\"app aikido dev_ai-pentests_projects_116389_assessments_019d67d4-81c8-7dd2-bb9e-0a4a774b2c78_issues_sidebarIssue=20440423 (4)\" src=\"https://github.com/user-attachments/assets/8415553a-9f1e-4f73-929c-aa0d18a101ca\" />",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "open-webui"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.7.0"
      }, {
        "fixed" : "0.10.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/security/advisories/GHSA-gh7p-78x6-jw6m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-59222"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/commit/fbcdcf146b99b5002705060a8243eee769108f9e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/open-webui/open-webui"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/releases/tag/v0.10.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T17:04:55Z",
    "nvd_published_at" : "2026-07-09T17:17:03Z"
  }
}