CVE-2026-45667: Open WebUI Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-m69w-p7m4-585j",
  "modified" : "2026-05-19T16:00:43Z",
  "published" : "2026-05-14T20:28:02Z",
  "aliases" : [ "CVE-2026-45667" ],
  "summary" : "Open WebUI: Unauthenticated endpoint can trigger embedding generation (cost/DoS)",
  "details" : "### Summary\nGET `/api/v1/memories/ef` is accessible without authentication and executes `request.app.state.EMBEDDING_FUNCTION(...)`. This allows any unauthenticated caller to trigger embedding generation which can lead to direct cost exposure if a paid provider is used.\nCode reference: `backend/open_webui/routers/memories.py` (@router.get(\"/ef\") -> calls `request.app.state.EMBEDDING_FUNCTION(\"hello world\"))`.\n\n\n### Details\nGET `/api/v1/memories/ef` is reachable without authentication and triggers request.app.state.EMBEDDING_FUNCTION(\"hello world\"). This crosses an intended security boundary by allowing unauthenticated users to invoke potentially expensive embedding computation and/or paid upstream embedding APIs.\n\n### PoC\n1. Start Open WebUI in default configuration (no special env hardening; default ENABLE_MEMORIES is true).\n2. From an unauthenticated client (no cookies/Authorization header), call:\n      curl -i http://\\<host\\>:\\<port\\>/api/v1/memories/ef\n   3. Observe the server performs embedding generation and returns a response like:\n   - HTTP 200 with JSON containing the result.\n\nHow it can be abused / attacker actions:\n\n- Send repeated requests to `/api/v1/memories/ef` to:\n  - consume CPU/GPU resources (DoS)\n  - generate sustained outbound usage to embedding providers if configured (cost + rate-limit exhaustion)\n  - degrade latency/availability for legitimate users\n \n### Impact\nIf embeddings are configured to use paid/remote providers (OpenAI/Azure/etc), an attacker can generate unlimited requests and incur charges.\n\n## Resolution\n\nFixed in commit [e5035ea31](https://github.com/open-webui/open-webui/commit/e5035ea31e179977e805a7032c979ff59a71860a), first released in **v0.8.0** (Feb 2026). The `/api/v1/memories/ef` route was removed entirely. It was a diagnostic/debug-style endpoint that hard-coded `\"hello world\"` through the embedding function without any authentication dependency; there was no legitimate caller that depended on it, so deletion was the cleaner fix than retrofitting auth. Users on `>= 0.8.0` are not affected.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "open-webui"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.7.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/security/advisories/GHSA-m69w-p7m4-585j"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45667"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/commit/e5035ea31e179977e805a7032c979ff59a71860a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/open-webui/open-webui"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/releases/tag/v0.8.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-862" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T20:28:02Z",
    "nvd_published_at" : "2026-05-15T22:16:56Z"
  }
}