CVE-2026-115922 ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115922?
CVE-2026-115922 is a medium-severity vulnerability in onnx, published on 26 Oct 2026.
Official description
Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. Prior to 1.22.0, _unpack_2bit() and _unpack_4bit() resize unpacked arrays according to attacker-controlled TensorProto.dims without verifying that raw_data or int32_data encodes the declared number of elements. Materializing an untrusted UINT2, INT2, UINT4, INT4, or FLOAT4E2M1 tensor through onnx.numpy_helper.to_array() or onnx.reference.ReferenceEvaluator can therefore expand a small packed payload into a disproportionately large allocation and exhaust memory. This issue is fixed in version 1.22.0.
Weakness: CWE-789
Which versions are affected by CVE-2026-115922?
2 open source packages ship an affected version, including onnx.
| Package | Affected | Fixed in |
|---|---|---|
onnx PyPI | All versions | 1.22.0 |
onnx PyPI | All versions | 1.22.0 |
How do I fix CVE-2026-115922?
Upgrade onnx to 1.22.0 or later.
Is CVE-2026-115922 being exploited?
There is no known exploitation of CVE-2026-115922 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-115922, ECHO-4a0c-5767-8d02, GHSA-q69g-f4f5-v8m7, UBUNTU-CVE-2026-115922.