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Fencer Vulns
high 7.1

CVE-2026-49114 json

ONNX symlink-following and path-traversal arbitrary file write

published 2026-04-01 7 mo ago modified 2026-10-15 24 d ago also GHSA-q56x-g2fj-4rj6 , PYSEC-2026-3876 , EUVD-2026-63995

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi onnx 1.21.0
  • ONNX ONNX 1.21.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-49114 updated cvss 7.3

onnx: ONNX: Arbitrary file write via symlink following and path traversal

  • Red Hat OpenShift AI 2.25 rhoai/odh-openvino-model-server-rhel9 1791275700
    fixed: vendor fix RHSA-2026:87410
  • Red Hat OpenShift AI 3.4 rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9 1791829182, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9 1791868244, rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9 1791829615, rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9 1791868194, rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9 1791829530, rhoai/odh-pipeline-runtime-datascience-cpu-py312-rhel9 1791829804, +8 more
    fixed: vendor fix RHSA-2026:84734
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-mlserver-rhel9, rhoai/odh-mlserver-cuda-rhel9 Red Hat OpenShift AI 2.25 rhoai/odh-rhel9-operator 1792570619, rhoai/odh-vllm-cpu-rhel9 1792018436, rhoai/odh-dashboard-rhel9 1791853525, rhoai/odh-modelmesh-rhel9 1790881700, rhoai/odh-operator-bundle 1792571069, rhoai/odh-vllm-cuda-rhel9 1791358976, +65 more Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1791509689, rhoai/rhai-cli-rhel9 1791509689, rhoai/odh-automl-rhel9 1791535789, rhoai/odh-mlflow-rhel9 1791865967, rhoai/odh-autorag-rhel9 1791557539, rhoai/odh-trainer-rhel9 1791869783, +86 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa vex VA-26-233-01 updated cvss 7.1

ONNX symlink-following and path-traversal arbitrary file write

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
CNA 4.0 6.8 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
CNA 4.0 6.8 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
OSV 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
GitHub 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi onnx
<1.21.0
1.21.0

Affected products

  • ONNX ONNX

Classification

Weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-59 Improper Link Resolution Before File Access

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.