GHSA-CMW6-HCPP-C6JP

Vulnerability from github – Published: 2026-04-01 21:13 – Updated: 2026-04-01 21:13
VLAI?
Summary
ONNX: Arbitrary File Read via ExternalData Hardlink Bypass in ONNX load
Details

Summary

The issue is in onnx.load — the code checks for symlinks to prevent path traversal, but completely misses hardlinks, which is the problem, since a hardlink looks exactly like a regular file on the filesystem.

The Real Problem

The validator in onnx/checker.cc only calls is_symlink() and never checks the inode or st_nlink, so a hardlink walks right through every security check without any issues.

Impact

Especially dangerous in AI supply chain scenarios like HuggingFace — a single malicious model is enough to silently steal secrets from the victim's machine without them noticing anything.

Severity ?
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.20.1"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "onnx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.21.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34446"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22",
      "CWE-61"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-01T21:13:37Z",
    "nvd_published_at": "2026-04-01T18:16:30Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nThe issue is in `onnx.load` \u2014 the code checks for symlinks to prevent path traversal, but completely misses hardlinks, which is the problem, since a hardlink looks exactly like a regular file on the filesystem.\n\n### The Real Problem\nThe validator in `onnx/checker.cc` only calls `is_symlink()` and never checks the inode or `st_nlink`, so a hardlink walks right through every security check without any issues.\n\n### Impact\nEspecially dangerous in AI supply chain scenarios like HuggingFace \u2014 a single malicious model is enough to silently steal secrets from the victim\u0027s machine without them noticing anything.",
  "id": "GHSA-cmw6-hcpp-c6jp",
  "modified": "2026-04-01T21:13:37Z",
  "published": "2026-04-01T21:13:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/onnx/onnx/security/advisories/GHSA-cmw6-hcpp-c6jp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34446"
    },
    {
      "type": "WEB",
      "url": "https://github.com/onnx/onnx/commit/4755f8053928dce18a61db8fec71b69c74f786cb"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/onnx/onnx"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ONNX: Arbitrary File Read via ExternalData Hardlink Bypass in ONNX load"
}


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