GHSA-486p-g8x4-77mg: Duplicate Advisory ONNX: TOCTOU Arbitrary File Read/write Vulnerability

MODERATE
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CVSS 7.1
CWE-22
Published
Advisory Summary

GHSA-486p-g8x4-77mg is a MODERATE (CVSS 7.1) onnx: toctou arbitrary file read/write vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Duplicate Advisory libraries in the PyPI ecosystem. The issue involves onnx: toctou arbitrary file read/write in save_external_dat. Remediation is available in the latest vendor maintenance releases.

GHSA-486p-g8x4-77mg at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-486p-g8x4-77mg
Severity MODERATE
CVSS v3.1 Base Score 7.1
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Duplicate Advisory
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability High (A:H)

How to Fix GHSA-486p-g8x4-77mg

To remediate this vulnerability, upgrade all affected Duplicate Advisory dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

onnx fixed: Latest secure release 
pip install onnx>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show onnx

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-486p-g8x4-77mg, inspect your installed packages using pip:

pip show onnx

Analyze the terminal output to locate any version of Duplicate Advisory in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show onnx command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Duplicate Advisory, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-q56x-g2fj-4rj6. This link is maintained to preserve external references. ## Original Description 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.

GHSA-486p-g8x4-77mg Affected Duplicate Advisory Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
onnx
pypi/onnx
PyPI
≤ 1.20.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6
NVD — GHSA-486p-g8x4-77mg NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49114
raw.githubusercontent.com/cisagov/csaf/develo... WEB
https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json
CVE Official Record — GHSA-486p-g8x4-77mg CVE
https://www.cve.org/CVERecord?id=CVE-2026-49114

Frequently Asked Questions

What is GHSA-486p-g8x4-77mg?
GHSA-486p-g8x4-77mg is a security vulnerability in Duplicate Advisory involving ONNX: TOCTOU arbitrary file read/write in save_external_dat under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Duplicate Advisory versions are affected?
Affected versions include releases prior to current release patches across affected packages: onnx.
What version fixes GHSA-486p-g8x4-77mg?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is onnx affected?
Yes, onnx is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of GHSA-486p-g8x4-77mg?
GHSA-486p-g8x4-77mg has a CVSS v3.1 base score of 7.1 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H.
What CWE is associated with GHSA-486p-g8x4-77mg?
GHSA-486p-g8x4-77mg is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check PyPI dependencies for GHSA-486p-g8x4-77mg?
Run the dependency tree command: 'pip show onnx'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-486p-g8x4-77mg",
  "modified" : "2026-09-08T20:57:28Z",
  "published" : "2026-08-21T18:34:56Z",
  "withdrawn" : "2026-09-08T20:57:28Z",
  "aliases" : [ ],
  "summary" : "Duplicate Advisory: ONNX: TOCTOU arbitrary file read/write in save_external_dat ",
  "details" : "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of GHSA-q56x-g2fj-4rj6. This link is maintained to preserve external references.\n\n## Original Description\nIn 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" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "onnx"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.20.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-49114"
  }, {
    "type" : "WEB",
    "url" : "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json"
  }, {
    "type" : "WEB",
    "url" : "https://www.cve.org/CVERecord?id=CVE-2026-49114"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-08T20:57:28Z",
    "nvd_published_at" : "2026-08-21T16:17:17Z"
  }
}