CVE-2026-115922
ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs
- State
- Published
- Severity
- 6.2 Medium
- Published
- Oct 26, 2026
- Updated
- Oct 30, 2026
- Reserved
- Oct 23, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.2 Medium | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
Weaknesses
- CWE-789 Memory Allocation with Excessive Size Value
Affected Products
| Product | Versions |
|---|---|
onnxonnx |
|
References
- https://github.com/onnx/onnx/security/advisories/GHSA-q69g-f4f5-v8m7
- https://github.com/onnx/onnx/pull/8033
- https://github.com/onnx/onnx/pull/8038
- https://github.com/onnx/onnx/pull/8066
- https://github.com/onnx/onnx/commit/05c1bc3bceceb8d3cf11e9e7fc7f19f971c44988
- https://github.com/onnx/onnx/commit/8de2cf6aa47928e6515ac6d9e1a8b4758886a7df
- https://github.com/onnx/onnx/commit/dce5876d6cc6cc30157af7d26a752ef44976da8e
- https://github.com/onnx/onnx/releases/tag/v1.22.0
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.