pyLoad 0.5.0b3.dev89 Uploaded File Name /json/upload path traversal

Summaryinfo

A vulnerability classified as critical has been found in pyLoad 0.5.0b3.dev89. The affected element is an unknown function of the file /json/upload of the component Uploaded File Name Handler. This manipulation causes path traversal. This vulnerability appears as CVE-2025-54140. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in pyLoad 0.5.0b3.dev89. Affected by this vulnerability is some unknown processing of the file /json/upload of the component Uploaded File Name Handler. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

pyLoad is a free and open-source Download Manager written in pure Python. In version 0.5.0b3.dev89, an authenticated path traversal vulnerability exists in the /json/upload endpoint of pyLoad. By manipulating the filename of an uploaded file, an attacker can traverse out of the intended upload directory, allowing them to write arbitrary files to any location on the system accessible to the pyLoad process. This may lead to: Remote Code Execution (RCE), local privilege escalation, system-wide compromise, persistence, and backdoors. This is fixed in version 0.5.0b3.dev90.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2025-54140 since 07/17/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Upgrading to version 0.5.0b3.dev90 eliminates this vulnerability. Applying the patch fc4b136e9c4e7dcbb8e467ae802cb2c3f70a71b0 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-22382). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• pyLoad

Version

• 0.5.0b3.dev89

License

• open-source

Website

• Product: https://github.com/pyload/pyload/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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