CVE-2026-45299: Open webui Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6gh2-q7cp-9qf6",
  "modified" : "2026-05-19T15:57:56Z",
  "published" : "2026-05-14T20:15:19Z",
  "aliases" : [ "CVE-2026-45299" ],
  "summary" : "Open WebUI has Stored Cross-Site Scripting In Profile Picture",
  "details" : "## Summary\n\nThe `profile_image_url` field on the user profile update form accepted arbitrary `data:` URI values without MIME-type validation. Two distinct attack paths were independently demonstrated by separate reporters:\n\n1. **`data:text/html;base64,...` in a new browser tab** (raresvis, 2025-04-17) — when a victim right-clicks a user's profile picture and chooses \"Open image in new tab\", the browser navigates to the data: URL and executes embedded scripts in the `data:` origin. Limited to social-engineering / redirect attacks because the script does not run in the application origin.\n\n2. **`data:image/svg+xml;base64,...` re-served by the application origin** (Gh05t666nero, 2026-01-09) — `GET /api/v1/users/{user_id}/profile/image` decoded the base64 and returned `StreamingResponse(media_type=<user-controlled>)` extracted from the `data:` header. With `media_type=image/svg+xml` and `Content-Disposition: inline`, the SVG-embedded scripts executed in the **application origin**, enabling JWT theft from `localStorage` and full account takeover of any user — including admins — who loaded the malicious profile image URL.\n\nBoth attack paths share the same root cause (lack of MIME-type validation on `profile_image_url`) and are closed by the same fix.\n\n## Vulnerable code (v0.7.0)\n\n`backend/open_webui/routers/users.py` `get_user_profile_image_by_id()`:\n\n```python\nelif user.profile_image_url.startswith(\"data:image\"):\n    header, base64_data = user.profile_image_url.split(\",\", 1)\n    image_data = base64.b64decode(base64_data)\n    image_buffer = io.BytesIO(image_data)\n    media_type = header.split(\";\")[0].lstrip(\"data:\")  # user-controlled\n    return StreamingResponse(\n        image_buffer,\n        media_type=media_type,\n        headers={\"Content-Disposition\": \"inline\"},\n    )\n```\n\n## Fix\n\nCommit `773787c74` (2026-02-11), first contained in tag **v0.8.0**, applies the `validate_profile_image_url` field validator to every form that accepts `profile_image_url` (`UserModel`, `UpdateProfileForm`, `SignupForm` in `backend/open_webui/models/users.py` and `backend/open_webui/models/auths.py`). The validator explicitly rejects `data:image/svg+xml` and any non-image data URI, allowing only `data:image/{png,jpeg,gif,webp};base64` plus known internal paths and `http(s)://` URLs. This blocks both attack vectors at form submission time, so a malicious URL can no longer be persisted to the database.\n\n## Credits\n\n- **raresvis** — discovered the `data:text/html`-via-new-tab path\n- **Gh05t666nero** — discovered the `data:image/svg+xml`-via-server-side path (the more severe origin-XSS vector that determined the consolidated CVSS)\n\nPer our Report Handling policy, the cluster is consolidated into the earliest filing with credit to every reporter who demonstrated a distinct exploitation path.\n\n## Affected / patched versions\n\n- Affected: `< 0.8.0`\n- Patched: `>= 0.8.0`",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "open-webui"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-webui/open-webui/security/advisories/GHSA-6gh2-q7cp-9qf6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-45299"
  }, {
    "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-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-14T20:15:19Z",
    "nvd_published_at" : "2026-05-15T22:16:53Z"
  }
}