Quick answers
- Is CVE-2026-63632 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-63632 being exploited in the wild.
- How severe is CVE-2026-63632?
- Low severity, with a CVSS score of 3.3, published 18 August 2026.
- Which products and versions are affected?
- onnx (PyPI) >= 1.3.0, <= 1.21.0, ECOSYSTEM:introduced=1.3.0,fixed=1.22.0.
- Is there a fix for CVE-2026-63632?
- Yes. onnx (PyPI): upgrade to 1.22.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-63632 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-63632?
- Check whether you run onnx (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- onnx (PyPI): upgrade to 1.22.0 or later
pip install "onnx>=1.22.0"
Technical details
A heap-buffer-overflow READ exists in the Gemm_7_6::adapt_gemm_7_6() function within the ONNX version converter. The vulnerability is caused by a lack of rank validation when processing input tensors during an opset downgrade from version 7 to 6. Specifically, the adapter attempts to access dimensions (e.g., B_shape[1]) of input tensors without verifying if the tensor has the required number of dimensions. An attacker can exploit this by providing a model with undersized input shapes, leading to a 16-byte out-of-bounds read. This can result in a crash or the propagation of adjacent heap data into the converted model's output shapes. The issue is fixed in ONNX version 1.22.0.
Affected products
- ONNX onnx >= 1.3.0, <= 1.21.0
Identifiers
- CVE-2026-63632
- GHSA-p893-rvq9-2xf9
- PYSEC-2026-3587
Timeline
- 2026-07-01: disclosed
- 2026-07-24: advisory: GitHub Advisory published
- 1.22.0: patched