Out-of-bounds Read Vulnerability in Open Neural Network Exchange by ONNX

CVE-2026-63632

What is CVE-2026-63632?

The Open Neural Network Exchange (ONNX) has a vulnerability in its version converter that can lead to an out-of-bounds read. Specifically, in the method 'onnx.version_converter.convert_version()', if a Gemm node has input tensors with fewer than two dimensions, it accesses B_shape[1], A_shape[0], or A_shape[1] without performing a rank check. This flaw can result in a process crash during a downgrade from opset 7 to 6, affecting the stability of applications relying on ONNX for machine learning interoperability. The issue has been addressed and fixed in version 1.22.0.

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