Is CVE-2026-49114 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-49114 being exploited in the wild.

How severe is CVE-2026-49114?

High severity, with a CVSS score of 7.1, published 21 August 2026.

Which products and versions are affected?

onnx (PyPI) ECOSYSTEM:introduced=0,fixed=1.21.0.

Is there a fix for CVE-2026-49114?

Yes. onnx (PyPI): upgrade to 1.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-49114 attacked?

It is attacked with local access.

Am I affected by CVE-2026-49114?

Check whether you run onnx (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-49114: ONNX save_external_data symlink-following file write

CVE-2026-49114 · Severity: high · CVSS 7.1 · Published 2026-08-21

ONNX is a machine learning model format and runtime library used to serialize and load neural network models. The save_external_data function contains a symlink-following vulnerability that allows a local attacker with directory write access to redirect file writes to arbitrary locations (such as SSH keys or application config files), potentially leading to unauthorized access or system compromise.

Technologies: onnx (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-49114 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-49114 being exploited in the wild.
How severe is CVE-2026-49114?: High severity, with a CVSS score of 7.1, published 21 August 2026.
Which products and versions are affected?: onnx (PyPI) ECOSYSTEM:introduced=0,fixed=1.21.0.
Is there a fix for CVE-2026-49114?: Yes. onnx (PyPI): upgrade to 1.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-49114 attacked?: It is attacked with local access.
Am I affected by CVE-2026-49114?: Check whether you run onnx (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

onnx (PyPI): upgrade to 1.21.0 or later
```
pip install "onnx>=1.21.0"
```

Technical details

A TOCTOU (time-of-check time-of-use) race condition exists in the save_external_data method in external_data_helper.py. The function checks if an external data file exists using os.path.isfile() and then opens it for writing without the O_NOFOLLOW or O_EXCL flags. An attacker with write access to the target directory can plant a symlink between the check and the open call, causing the victim's write to follow the symlink and overwrite any file the victim has write permissions to (e.g., ~/.ssh/authorized_keys, cron files, or application configs). The vulnerability requires local access and user interaction (loading and saving a model), but enables arbitrary file write as the victim user. Fixed in version 1.21.0.

Affected products

ONNX ONNX before 1.21.0

Identifiers

CVE-2026-49114
GHSA-q56x-g2fj-4rj6
PYSEC-2026-3876

Timeline

2026-08-21: disclosed
2026-08-21: patched: Version 1.21.0

References

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