ONNX up to 1.21.x Version Converter gemm_7_6.h Gemm_7_6::adapt_gemm_7_6 out-of-bounds

Summaryinfo

A vulnerability identified as problematic has been detected in ONNX up to 1.21.x. This affects the function Gemm_7_6::adapt_gemm_7_6 of the file onnx/version_converter/adapters/gemm_7_6.h of the component Version Converter. This manipulation causes out-of-bounds. The identification of this vulnerability is CVE-2026-63632. The attack can only be executed locally. There is no exploit available.

Detailsinfo

A vulnerability has been found in ONNX up to 1.21.x and classified as problematic. Affected by this vulnerability is the function Gemm_7_6::adapt_gemm_7_6 of the file onnx/version_converter/adapters/gemm_7_6.h of the component Version Converter. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect availability. The summary by CVE is:

Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. From 1.3.0 until 1.22.0, onnx.version_converter.convert_version() can perform an out-of-bounds read in Gemm_7_6::adapt_gemm_7_6() in onnx/version_converter/adapters/gemm_7_6.h when a Gemm node has input tensors with fewer than two dimensions because B_shape[1], A_shape[0], or A_shape[1] is accessed without a rank check, potentially causing a process crash during an opset 7 to 6 downgrade. This issue is fixed in version 1.22.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-63632 since 07/17/2026. The exploitation appears to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 1.22.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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