ONNX up to 1.21.x Scan Inference ScanInferenceFunction null pointer dereference

Summaryinfo

A vulnerability has been found in ONNX up to 1.21.x and classified as problematic. Affected by this vulnerability is the function ScanInferenceFunction of the component Scan Inference. The manipulation leads to null pointer dereference. This vulnerability is traded as CVE-2026-115921. An attack has to be approached locally. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in ONNX up to 1.21.x and classified as problematic. This issue affects the function ScanInferenceFunction of the component Scan Inference. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. From 1.4.0 until 1.22.0, ScanInferenceFunction, ScanInferenceFunction_opset8, and ScanInferenceFunction_opset9 do not safely validate the required num_scan_inputs attribute. A missing attribute is dereferenced as a null pointer, while a negative value is converted to size_t and can reach an exceptional oversized allocation path. An untrusted model can therefore terminate or disrupt shape inference, including a negative-value model that can pass onnx.checker.check_model(). This issue is fixed in version 1.22.0.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-115921 since 10/23/2026. The exploitation is known to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

Upgrading to version 1.22.0 eliminates this vulnerability.

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Productinfo

Name

• ONNX

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21

Website

• Product: https://github.com/onnx/onnx/

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