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

Quick assessment

Affected

onnx onnx

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Open Neural Network Exchange（ONNX）是一项用于机器学习互操作性的开放标准。在 1.22.0 版本之前，和函数会根据攻击者控制的对解压后的数组进行重缩放，却未验证或是否确实编码了声明的元素数量。因此，通过或实例化不可信的 UINT2、INT2、UINT4、INT4 或 FLOAT4E2M1 张量时，攻击者可将一个小型的压缩载荷扩展为不成比例的巨大内存分配，从而导致内存耗尽。该问题已在 1.22.0 版本中修复。

CVSS 6.2 · Medium Updated Oct 27, 2026

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

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

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

未经控制的内存分配

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
onnx	onnx	< 1.22.0	-

II. Public POCs for CVE-2026-115922

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-115922

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Patches & Fixes for CVE-2026-115922 (4)

Vendor Advisories for CVE-2026-115922 (1)

🔗 Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs · Advisory · onnx/onnx · GitHub Read full article x_refsource_CONFIRM

Vendor Pages for CVE-2026-115922 (1)

🔗 Release v1.22.0 · onnx/onnx · GitHub x_refsource_MISC

https://www.cve.org/CVERecord?id=CVE-2026-115922

Same Patch Batch · onnx · 2026-10-26 · 4 CVEs total

CVE-2026-115921	6.2 MEDIUM	ONNX: Null Pointer Dereference in ScanInferenceFunction Due to Missing Required Attribute
CVE-2026-115920	6.2 MEDIUM	ONNX: Out-of-bounds read in ConvTranspose shape inference via undersized weight rank
CVE-2026-115919	6.2 MEDIUM	ONNX: Out-of-Bounds Read in RNN/GRU/LSTM Shape Inference (Old Opsets, Missing Rank Check)

IV. Related Vulnerabilities

Same product: onnx

Same vendor: onnx

Same weakness: CWE-789