CVE-2025-1889
📋 TL;DR
CVE-2025-1889 is a vulnerability in picklescan versions before 0.0.22 where the tool only checks standard pickle file extensions (.pkl, .pickle, .pckl) for malicious content. Attackers can bypass security scans by using non-standard file extensions for malicious pickle files, potentially allowing arbitrary code execution. This affects anyone using picklescan to validate machine learning models or other pickle-serialized data.
💻 Affected Systems
- picklescan
📦 What is this software?
Picklescan by Mmaitre314
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise if malicious pickle files are loaded by vulnerable applications, potentially leading to data theft, ransomware deployment, or complete system takeover.
Likely Case
Arbitrary code execution in the context of the application loading the pickle file, allowing attackers to steal sensitive data, install backdoors, or pivot to other systems.
If Mitigated
Limited impact if proper input validation and file extension checking is implemented separately from picklescan, or if pickle loading is restricted to trusted sources.
🎯 Exploit Status
Exploitation requires convincing a target to process a malicious pickle file with non-standard extension, but the bypass technique is simple and well-documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.0.22
Vendor Advisory: https://github.com/mmaitre314/picklescan/security/advisories/GHSA-655q-fx9r-782v
Restart Required: No
Instructions:
1. Update picklescan to version 0.0.22 or later using pip: pip install --upgrade picklescan>=0.0.22
2. Verify the update with: picklescan --version
3. Re-run security scans on all pickle files to ensure comprehensive coverage.
🔧 Temporary Workarounds
Manual file extension validation
allImplement additional validation to check for pickle files with non-standard extensions before processing
# Example Python script to check file extensions
import os
import pickle
file_extensions = ['.pkl', '.pickle', '.pckl', '.pth', '.pt', '.model', '.joblib', '.sav']
# Add any other extensions your application uses for pickle files
for file in files_to_check:
if any(file.endswith(ext) for ext in file_extensions):
# Run picklescan on this file
os.system(f'picklescan {file}')
🧯 If You Can't Patch
- Implement strict allowlisting of file extensions for pickle processing, rejecting any files with non-standard extensions
- Only load pickle files from trusted, verified sources and implement digital signature verification for pickle files
🔍 How to Verify
Check if Vulnerable:
Run: picklescan --version and check if version is below 0.0.22Check Version:
picklescan --versionVerify Fix Applied:
1. Update to picklescan>=0.0.22
2. Test with a safe pickle file using non-standard extension (e.g., .malicious) to confirm it's now detected
3. Verify version shows 0.0.22 or higher📡 Detection & Monitoring
Log Indicators:
- Failed or bypassed picklescan scans
- Pickle files with unusual extensions being processed
- Unexpected process execution following pickle file loading
Network Indicators:
- Downloads of pickle files with non-standard extensions
- Unusual outbound connections from processes that load pickle files
SIEM Query:
process.name:picklescan AND event.outcome:failure OR file.extension:(NOT (.pkl OR .pickle OR .pckl)) AND file.type:pickle