GHSA-75M9-98V2-HJPM

Vulnerability from github – Published: 2026-05-12 18:30 – Updated: 2026-05-18 20:24
VLAI
Summary
PyTorch Lightning load_from_checkpoint has an insecure checkpoint deserialization
Details

PyTorch-Lightning versions 2.6.0 and earlier contain an insecure deserialization vulnerability (CWE-502) in the checkpoint loading mechanism. The LightningModule.load_from_checkpoint() method, which is commonly used to load saved model states, internally calls torch.load() without setting the security-restrictive weights_only=True parameter. This default behavior allows the deserialization of arbitrary Python objects via the Pickle module. A remote attacker can exploit this by providing a maliciously crafted checkpoint file, leading to arbitrary code execution on the victim's system when the file is loaded.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pytorch-lightning"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "2.6.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-31221"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-18T20:24:38Z",
    "nvd_published_at": "2026-05-12T16:16:14Z",
    "severity": "HIGH"
  },
  "details": "PyTorch-Lightning versions 2.6.0 and earlier contain an insecure deserialization vulnerability (CWE-502) in the checkpoint loading mechanism. The LightningModule.load_from_checkpoint() method, which is commonly used to load saved model states, internally calls torch.load() without setting the security-restrictive weights_only=True parameter. This default behavior allows the deserialization of arbitrary Python objects via the Pickle module. A remote attacker can exploit this by providing a maliciously crafted checkpoint file, leading to arbitrary code execution on the victim\u0027s system when the file is loaded.",
  "id": "GHSA-75m9-98v2-hjpm",
  "modified": "2026-05-18T20:24:38Z",
  "published": "2026-05-12T18:30:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31221"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Lightning-AI/pytorch-lightning"
    },
    {
      "type": "WEB",
      "url": "https://www.notion.so/CVE-2026-31221-35d1e1393188815f8db7c4fd08076639"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "PyTorch Lightning load_from_checkpoint has an insecure checkpoint deserialization"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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Detection rules are retrieved from Rulezet.