Medium 6.2Published Oct 26, 2026

CVE-2026-115922ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs

Updated under an hour ago (Oct 29, 2026, 8:40 PM ET)

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No exploitation reported and no EPSS estimate yet.

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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.

CVSS: 6.2 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-789
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Oct 26, 2026
First seen by InfoSec Signals: Oct 26, 2026

Affected products

Affected products

onnx onnx onnx:onnx (from the name)	before 1.22.0	CNA record

References

References

https://github.com/onnx/onnx/security/advisories/GHSA-q69g-f4f5-v8m7	x-refsource-confirm
https://github.com/onnx/onnx/pull/8033	x-refsource-misc
https://github.com/onnx/onnx/pull/8038	x-refsource-misc
https://github.com/onnx/onnx/pull/8066	x-refsource-misc
https://github.com/onnx/onnx/commit/05c1bc3bceceb8d3cf11e9e7fc7f19f971c44988	x-refsource-misc
https://github.com/onnx/onnx/commit/8de2cf6aa47928e6515ac6d9e1a8b4758886a7df	x-refsource-misc
https://github.com/onnx/onnx/commit/dce5876d6cc6cc30157af7d26a752ef44976da8e	x-refsource-misc
https://github.com/onnx/onnx/releases/tag/v1.22.0	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.