{
  "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-2026-54017"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-17T17:55:28Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nThe terminal-server reverse proxy in `backend/open_webui/routers/terminals.py` does not fully confine the user-controlled `path` segment before forwarding it to an admin-configured terminal server. An authenticated user who has been granted access to a terminal server can craft `path` values containing encoded `../` traversal sequences that escape the intended path (or policy) scope on that server, reaching unintended endpoints and files on the terminal-server host. Where the terminal server fans requests out to internal services, this also gives SSRF-style reach into those services.\n\nThis is a separate code path from the `/api/v1/retrieval/process/web` SSRF (GHSA-c6xv-rcvw-v685), with its own input. Two distinct vectors are consolidated here:\n\n1. Raw path forwarding / single-encoded traversal (original report).\n2. A bypass of the subsequently-added `_sanitize_proxy_path` mitigation using double-encoded dots (`%252e%252e`).\n\nThe attacker-controlled input is the request `path`, supplied by the non-admin user, not anything an administrator configures, so this is not an admin-trust / Rule-9 situation.\n\n### Affected code\n\nThe proxy route forwards an arbitrary trailing path to the configured terminal server:\n\n```python\n# routers/terminals.py\n@router.api_route(\u0027/{server_id}/{path:path}\u0027, methods=PROXY_METHODS)\nasync def proxy_terminal(server_id, path, request, user=Depends(get_verified_user)):\n    ...\n    safe_path = _sanitize_proxy_path(path)\n    if safe_path is None:\n        return JSONResponse({\u0027error\u0027: \u0027Invalid path\u0027}, status_code=400)\n    target_url = f\u0027{base_url}/{safe_path}\u0027\n    policy_id = connection.get(\u0027policy_id\u0027)\n    if policy_id:\n        target_url = f\u0027{base_url}/p/{policy_id}/{safe_path}\u0027\n```\n\nAccess requires `has_connection_access(user, connection, ...)`, i.e. a non-admin user the administrator has granted to that terminal server.\n\n### Vector 1 \u2014 single-encoded traversal (original)\n\nThe path was originally concatenated to the base URL with no sanitization (`target_url = f\"{base_url}/{path}\"`), so single-encoded traversal escaped the intended scope:\n\n```\nGET /api/v1/terminals/server1/..%2F..%2F..%2Finternal-api/secrets\n# proxied to: {base_url}/../../../internal-api/secrets\n```\n\nThis vector is closed at HEAD: `_sanitize_proxy_path` now URL-decodes once, runs `posixpath.normpath`, strips leading slashes, and rejects results beginning with `..` (`unquote(\u0027..%2F..%2F\u0027) -\u003e \u0027../../\u0027 -\u003e normpath -\u003e \u0027../..\u0027` -\u003e rejected).\n\n### Vector 2 \u2014 double-encoded bypass of `_sanitize_proxy_path`\n\n`_sanitize_proxy_path` decodes the path only once before the `..` check, so a double-encoded payload survives:\n\n```python\ndef _sanitize_proxy_path(path: str) -\u003e str | None:\n    decoded = unquote(path)                 # single decode pass only\n    normalized = posixpath.normpath(decoded)\n    cleaned = normalized.lstrip(\u0027/\u0027)\n    if cleaned.startswith(\u0027..\u0027) or cleaned == \u0027.\u0027:\n        return None\n    ...\n```\n\n`unquote(\u0027%252e%252e/secret\u0027)` yields `%2e%2e/secret` (not `..`), which `normpath` leaves unchanged and which does not start with `..`, so it passes the check. The proxy then forwards `{base_url}/%2e%2e/secret`, and the upstream terminal server decodes `%2e%2e` into `..` and resolves the traversal the check was meant to prevent.\n\n```\nGET /api/v1/terminals/server1/%252e%252e/%252e%252e/sensitive-file\n# passes _sanitize_proxy_path as %2e%2e/%2e%2e/sensitive-file\n# upstream decodes -\u003e ../../sensitive-file\n```\n\nThe `policy_id` form (`{base_url}/p/{policy_id}/{safe_path}`) is the higher-impact target: traversal escapes the policy namespace and reaches other policies or the terminal-server root.\n\n### Impact\n\nAn authenticated user with access to a terminal server can escape the intended path/policy scope on that server, reaching unintended endpoints and files, and, where the terminal server routes onward to internal services, reach those services. CWE-22 (Path Traversal) and CWE-918 (SSRF).\n\n### Fix\n\nDecode the proxy path until it is stable before normalising and checking, so no depth of encoding can smuggle a traversal sequence past the check to be re-decoded upstream:\n\n```python\ndecoded = path\nfor _ in range(8):\n    once = unquote(decoded)\n    if once == decoded:\n        break\n    decoded = once\nnormalized = posixpath.normpath(decoded)\ncleaned = normalized.lstrip(\u0027/\u0027)\nif cleaned.startswith(\u0027..\u0027) or cleaned == \u0027.\u0027:\n    return None\n```\n\nThis rejects `%2e%2e`, `%252e%252e`, `%25252e%25252e`, `..%2f..%2f`, etc., while leaving legitimate paths (including singly-encoded characters such as `%20`) intact.\n\n### Credits\n\n- **Tulgaaaaaaaa** \u2014 original report (terminal-proxy path SSRF / single-encoded traversal).\n- **sermikr0** \u2014 double-encoded (`%252e%252e`) bypass of the `_sanitize_proxy_path` mitigation.",
  "id": "GHSA-r2wg-2mcr-66rv",
  "modified": "2026-06-17T17:55:28Z",
  "published": "2026-06-17T17:55:28Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-r2wg-2mcr-66rv"
    },
    {
      "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:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI: Path traversal / SSRF in terminal server proxy via encoded path traversal"
}