Arbitrary File Creation Vulnerability in Picklescan
Summary
GHSA-m7j5-r2p5-c39r: picklescan vulnerable to arbitrary file create using logging.FileHandler. Affects picklescan versions < 1.0.1. Fixed in 1.0.1. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
Picklescan is a Python package designed for safe deserialization of pickle data. It aims to provide developers with tools to handle serialized data securely, preventing common vulnerabilities associated with untrusted data. However, it is susceptible to a significant vulnerability that allows unauthorized file creation through unsafe deserialization practices.
Vulnerability Detail
The vulnerability arises from unsafe pickle deserialization, which permits unauthenticated attackers to create arbitrary files on the server. By exploiting the logging.FileHandler class, attackers can bypass security measures that block remote code execution (RCE) attempts. This vulnerability allows the creation of zero-byte files in arbitrary locations, which can lead to filesystem pollution or logic disruption, potentially triggering denial of service (DoS) conditions or preventing applications from starting.
How To Fix
Latest published version: 1.0.5 as of 22 Oct 2026
pip install --upgrade "picklescan==1.0.5"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
1.0.1
This is the first release that contains the fix.
pip install --upgrade "picklescan==1.0.1"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, avoid deserializing untrusted pickle data. If you must use pickle, ensure that the data is from a trusted source and implement additional checks to validate the data before deserialization.
Conclusion
The Picklescan package has a vulnerability that allows arbitrary file creation through unsafe pickle deserialization. It is crucial for developers to update to the latest version to mitigate this risk and to avoid deserializing untrusted data. Utilizing tools like Vulert can help monitor for such vulnerabilities in real-time.
See every vulnerability recorded for picklescan →
FAQ
The vulnerability allows unauthorized file creation through unsafe pickle deserialization, enabling attackers to create zero-byte files in arbitrary locations.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which monitors and alerts for open-source vulnerabilities without requiring installation.
The impacts include filesystem pollution, logic disruption, and potential denial of service (DoS) conditions due to the creation of specific lock files.
Yes, a patch is available in version 1.0.1 of the Picklescan package. It is recommended to update to this version or later.
The CVSS score of this vulnerability is 5.5, indicating a moderate severity level.
References
Related vulnerabilities
Recent vulnerabilities recorded for picklescan.
