ubuntu-cve-2026-31221
Vulnerability from osv_ubuntu
Published
2026-05-12 16:16
Modified
2026-05-20 21:46
Summary
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
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libtorch-test",
            "binary_version": "1.8.1-4"
          },
          {
            "binary_name": "libtorch1.8",
            "binary_version": "1.8.1-4"
          },
          {
            "binary_name": "python3-torch",
            "binary_version": "1.8.1-4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "pytorch",
        "purl": "pkg:deb/ubuntu/pytorch@1.8.1-4?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.1-7",
        "1.8.1-4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libtorch-test",
            "binary_version": "2.6.0+dfsg-7"
          },
          {
            "binary_name": "libtorch2.6",
            "binary_version": "2.6.0+dfsg-7"
          },
          {
            "binary_name": "python3-torch",
            "binary_version": "2.6.0+dfsg-7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "pytorch",
        "purl": "pkg:deb/ubuntu/pytorch@2.6.0+dfsg-7?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.0+dfsg-5build1",
        "2.6.0+dfsg-7"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libtorch-test",
            "binary_version": "2.9.1+dfsg-1~exp1ubuntu2"
          },
          {
            "binary_name": "libtorch2.9",
            "binary_version": "2.9.1+dfsg-1~exp1ubuntu2"
          },
          {
            "binary_name": "python3-torch",
            "binary_version": "2.9.1+dfsg-1~exp1ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "pytorch",
        "purl": "pkg:deb/ubuntu/pytorch@2.9.1+dfsg-1~exp1ubuntu2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.6.0+dfsg-7",
        "2.6.0+dfsg-9",
        "2.9.1+dfsg-1~exp1ubuntu2"
      ]
    }
  ],
  "aliases": [],
  "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": "UBUNTU-CVE-2026-31221",
  "modified": "2026-05-20T21:46:15Z",
  "published": "2026-05-12T16:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-31221"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31221"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-31221"
  ]
}



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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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