CVE-2026-27489 ONNX: Path Traversal via Symlink
An attacker can read arbitrary files outside the intended directory via symlink path traversal in the ONNX library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27489?
CVE-2026-27489 is a high-severity path traversal vulnerability in onnx, published on 1 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. Prior to version 1.21.0, a path traversal vulnerability via symlink allows to read arbitrary files outside model or user-provided directory. This issue has been patched in version 1.21.0.
Which versions are affected by CVE-2026-27489?
3 open source packages ship an affected version, including onnx. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
onnx PyPI | All versions | 1.21.0 |
onnx PyPI | All versions | 1.21.0 |
onnx PyPI | All versions | 1.21.0 |
Products include Linuxfoundation Onnx.
How do I fix CVE-2026-27489?
Upgrade onnx to 1.21.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-27489 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27489 exists.
Other vulnerabilities in onnx
- CVE-2025-51480 Path traversal in n/a
- CVE-2024-5187 Arbitrary File Overwrite in download_model_with_test_data in onnx/onnx
- CVE-2026-34445 ONNX: Malicious ONNX models can crash servers by exploiting unprotected object settings.
- CVE-2026-28500 ONNX Untrusted Model Repository Warnings Suppressed by silent=True in onnx.hub.load() — Silent Supply-Chain Attack
- CVE-2022-25882 Directory Traversal in onnx
Sources
Also known as DEBIAN-CVE-2026-27489, ECHO-bbdd-cc38-c3a7, GHSA-3r9x-f23j-gc73, PYSEC-2026-2239, UBUNTU-CVE-2026-27489.