PYSEC-2026-2708

Vulnerability from pysec - Published: 2026-07-13 15:19 - Updated: 2026-07-13 16:05
VLAI
Details

Summary

The 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:

  1. 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.

  2. 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.

Both attack paths share the same root cause (lack of MIME-type validation on profile_image_url) and are closed by the same fix.

Vulnerable code (v0.7.0)

backend/open_webui/routers/users.py get_user_profile_image_by_id():

elif user.profile_image_url.startswith("data:image"):
    header, base64_data = user.profile_image_url.split(",", 1)
    image_data = base64.b64decode(base64_data)
    image_buffer = io.BytesIO(image_data)
    media_type = header.split(";")[0].lstrip("data:")  # user-controlled
    return StreamingResponse(
        image_buffer,
        media_type=media_type,
        headers={"Content-Disposition": "inline"},
    )

Fix

Commit 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.

Credits

  • raresvis — discovered the data:text/html-via-new-tab path
  • Gh05t666nero — discovered the data:image/svg+xml-via-server-side path (the more severe origin-XSS vector that determined the consolidated CVSS)

Per our Report Handling policy, the cluster is consolidated into the earliest filing with credit to every reporter who demonstrated a distinct exploitation path.

Affected / patched versions

  • Affected: < 0.8.0
  • Patched: >= 0.8.0
Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Impacted products
Name purl
open-webui pkg:pypi/open-webui
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui",
        "purl": "pkg:pypi/open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.8.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.124",
        "0.1.125",
        "0.2.0",
        "0.2.1",
        "0.2.2",
        "0.2.3",
        "0.2.4",
        "0.2.5",
        "0.3.0",
        "0.3.1",
        "0.3.10",
        "0.3.12",
        "0.3.13",
        "0.3.14",
        "0.3.15",
        "0.3.16",
        "0.3.17",
        "0.3.17.dev2",
        "0.3.17.dev3",
        "0.3.17.dev4",
        "0.3.17.dev5",
        "0.3.18",
        "0.3.19",
        "0.3.2",
        "0.3.20",
        "0.3.21",
        "0.3.22",
        "0.3.23",
        "0.3.24",
        "0.3.25",
        "0.3.26",
        "0.3.27",
        "0.3.27.dev1",
        "0.3.27.dev2",
        "0.3.27.dev3",
        "0.3.28",
        "0.3.29",
        "0.3.3",
        "0.3.30",
        "0.3.30.dev1",
        "0.3.30.dev2",
        "0.3.31",
        "0.3.31.dev1",
        "0.3.32",
        "0.3.33",
        "0.3.33.dev1",
        "0.3.34",
        "0.3.35",
        "0.3.4",
        "0.3.5",
        "0.3.6",
        "0.3.7",
        "0.3.8",
        "0.3.9",
        "0.4.0",
        "0.4.0.dev1",
        "0.4.0.dev2",
        "0.4.1",
        "0.4.2",
        "0.4.3",
        "0.4.4",
        "0.4.5",
        "0.4.6",
        "0.4.6.dev1",
        "0.4.7",
        "0.4.8",
        "0.5.0",
        "0.5.0.dev1",
        "0.5.0.dev2",
        "0.5.1",
        "0.5.10",
        "0.5.11",
        "0.5.12",
        "0.5.13",
        "0.5.14",
        "0.5.15",
        "0.5.16",
        "0.5.17",
        "0.5.18",
        "0.5.19",
        "0.5.2",
        "0.5.20",
        "0.5.3",
        "0.5.3.dev1",
        "0.5.4",
        "0.5.5",
        "0.5.6",
        "0.5.7",
        "0.5.8",
        "0.5.9",
        "0.6.0",
        "0.6.1",
        "0.6.10",
        "0.6.11",
        "0.6.12",
        "0.6.13",
        "0.6.14",
        "0.6.15",
        "0.6.16",
        "0.6.18",
        "0.6.19",
        "0.6.2",
        "0.6.20",
        "0.6.21",
        "0.6.22",
        "0.6.23",
        "0.6.24",
        "0.6.25",
        "0.6.26",
        "0.6.26.dev1",
        "0.6.27",
        "0.6.28",
        "0.6.29",
        "0.6.3",
        "0.6.30",
        "0.6.31",
        "0.6.32",
        "0.6.33",
        "0.6.34",
        "0.6.35",
        "0.6.36",
        "0.6.37",
        "0.6.38",
        "0.6.39",
        "0.6.4",
        "0.6.40",
        "0.6.41",
        "0.6.42",
        "0.6.43",
        "0.6.5",
        "0.6.6",
        "0.6.6.dev1",
        "0.6.7",
        "0.6.8",
        "0.6.9",
        "0.7.0",
        "0.7.1",
        "0.7.2"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45299",
    "GHSA-6gh2-q7cp-9qf6"
  ],
  "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) \u2014 when a victim right-clicks a user\u0027s 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) \u2014 `GET /api/v1/users/{user_id}/profile/image` decoded the base64 and returned `StreamingResponse(media_type=\u003cuser-controlled\u003e)` 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 \u2014 including admins \u2014 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** \u2014 discovered the `data:text/html`-via-new-tab path\n- **Gh05t666nero** \u2014 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: `\u003c 0.8.0`\n- Patched: `\u003e= 0.8.0`",
  "id": "PYSEC-2026-2708",
  "modified": "2026-07-13T16:05:11.296373Z",
  "published": "2026-07-13T15:19:05.784784Z",
  "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"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/open-webui"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-6gh2-q7cp-9qf6"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI has Stored Cross-Site Scripting In Profile Picture"
}



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