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ubuntu-cve-2026-49114
Vulnerability from osv_ubuntu
Published
2026-08-21 16:17
Modified
2026-09-02 16:18
Summary
Details

In ONNX before 1.21.0, the 'save_external_data' function builds the external-data file path from the model's external_data location field and opens it for writing without 'O_NOFOLLOW/O_EXCL', after a non-atomic 'os.path.isfile()' check. A local attacker with write access to the directory where a victim serializes external data can deterministically pre-plant a symlink that is being followed, causing the victim's write to append to any file the victim can write, e.g. ~/.ssh/authorized_keys, cron files, or application configs. Fixed in 1.21.0.

Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
6.8 (Medium)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libonnx-testdata",
            "binary_version": "1.7.0+dfsg-3ubuntu2"
          },
          {
            "binary_name": "libonnx1",
            "binary_version": "1.7.0+dfsg-3ubuntu2"
          },
          {
            "binary_name": "libonnxifi",
            "binary_version": "1.7.0+dfsg-3ubuntu2"
          },
          {
            "binary_name": "python3-onnx",
            "binary_version": "1.7.0+dfsg-3ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "onnx",
        "purl": "pkg:deb/ubuntu/onnx@1.7.0+dfsg-3ubuntu2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.0+dfsg-3build1",
        "1.7.0+dfsg-3build2",
        "1.7.0+dfsg-3ubuntu1",
        "1.7.0+dfsg-3ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libonnx-testdata",
            "binary_version": "1.14.1-2.1ubuntu0.1~esm1"
          },
          {
            "binary_name": "libonnx1t64",
            "binary_version": "1.14.1-2.1ubuntu0.1~esm1"
          },
          {
            "binary_name": "python3-onnx",
            "binary_version": "1.14.1-2.1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "onnx",
        "purl": "pkg:deb/ubuntu/onnx@1.14.1-2.1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.13.1-3",
        "1.13.1-3build1",
        "1.14.1-2",
        "1.14.1-2.1",
        "1.14.1-2.1build1",
        "1.14.1-2.1build2",
        "1.14.1-2.1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libonnx-testdata",
            "binary_version": "1.20.0-1"
          },
          {
            "binary_name": "libonnx1t64",
            "binary_version": "1.20.0-1"
          },
          {
            "binary_name": "python3-onnx",
            "binary_version": "1.20.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "onnx",
        "purl": "pkg:deb/ubuntu/onnx@1.20.0-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.17.0-3build1",
        "1.20.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "In ONNX before 1.21.0, the \u0027save_external_data\u0027 function builds the external-data file path from the model\u0027s external_data location field and opens it for writing without \u0027O_NOFOLLOW/O_EXCL\u0027, after a non-atomic \u0027os.path.isfile()\u0027 check. A local attacker with write access to the directory where a victim serializes external data can deterministically pre-plant a symlink that is being followed, causing the victim\u0027s write to append to any file the victim can write, e.g. ~/.ssh/authorized_keys, cron files, or application configs. Fixed in 1.21.0.",
  "id": "UBUNTU-CVE-2026-49114",
  "modified": "2026-09-02T16:18:21Z",
  "published": "2026-08-21T16:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-49114"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-49114"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-49114"
  ]
}



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