CVE-2026-115922

ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs

Published Oct 26, 2026 CVSS 3.1 · 6.2 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-q69g-f4f5-v8m7 ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Onnx
Onnx onnx
Vendors & Products Onnx
Onnx onnx
Type Values Removed Values Added
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.
Title ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs
Weaknesses CWE-789
References
Metrics cvssV3_1

{'score': 6.2, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 30, 2026, 5:40 PM
Reserved
Oct 23, 2026, 8:21 PM
Status
Awaiting Analysis
Published
Oct 26, 2026, 6:17 PM
Modified
Oct 30, 2026, 6:17 PM
Severity
Moderate
Public date
Oct 26, 2026, 5:31 PM