Overview
This report discusses the critical vulnerability identified as CVE-2025-54140 in the open-source Download Manager, pyLoad. This flaw, found in version 0.5.0b3.dev89, allows an attacker to exploit a path traversal vulnerability. It is significant because it can lead to remote code execution, local privilege escalation, system-wide compromise, and even the establishment of persistent backdoors.
Vulnerability Summary
CVE ID: CVE-2025-54140
Severity: High (CVSS: 7.5)
Attack Vector: Network
Privileges Required: User-level
User Interaction: Required
Impact: Potential system-wide compromise and data leakage
Affected Products
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Product | Affected Versions
pyLoad | 0.5.0b3.dev89
How the Exploit Works
The vulnerability exists in the /json/upload endpoint of pyLoad. An attacker, by manipulating the filename of an uploaded file, can traverse out of the intended upload directory. This allows them to write arbitrary files to any location on the system that is accessible to the pyLoad process.
Conceptual Example Code
The following is a conceptual example of how this vulnerability might be exploited:
POST /json/upload HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="../../../../etc/passwd"
Content-Type: text/plain
root:x:0:0:root:/root:/bin/bash
------WebKitFormBoundary7MA4YWxkTrZu0gWIn this example, an attacker uploads a file with a manipulated filename, aiming to overwrite the ‘/etc/passwd’ file, a critical system file in Unix-like operating systems. If the malicious upload is successful, the attacker could potentially gain root-level access to the system.
Mitigation Guidance
Users of pyLoad version 0.5.0b3.dev89 are advised to immediately upgrade to version 0.5.0b3.dev90 to mitigate this vulnerability. In cases where the upgrade cannot be promptly performed, employing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure.