Vulnerability · Published Oct 26, 2026 · Assigned by GitHub_M

CVE-2026-115921ONNX: Null Pointer Dereference in ScanInferenceFunction Due to Missing Required Attribute

Medium 6.2

In plain English

A medium-severity null pointer dereference in onnx from onnx. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.2Medium

Exploit odds (30 days)0.1%top 97.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	onnx	no fix listed	DEBIAN-CVE-2026-115921
Debian:13	onnx	no fix listed	DEBIAN-CVE-2026-115921
Debian:14	onnx	no fix listed	DEBIAN-CVE-2026-115921
PyPI	onnx	1.22.0	GHSA-m4pr-6v3c-6fgr
Ubuntu:22.04:LTS	onnx	no fix listed	UBUNTU-CVE-2026-115921
Ubuntu:26.04:LTS	onnx	no fix listed	UBUNTU-CVE-2026-115921
Ubuntu:26.10	onnx	no fix listed	UBUNTU-CVE-2026-115921

Affected products (as reported)

Vendor	Product	Versions
onnx	onnx	>= 1.4.0, < 1.22.0

Weakness: CWE-195, CWE-476 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/onnx/onnx/security/advisories/GHSA-m4pr-6v3c-6fgr x_refsource_CONFIRM
https://github.com/onnx/onnx/pull/7916 x_refsource_MISC
https://github.com/onnx/onnx/commit/dd6bc92ea39fd2274fd671f0734b0b8b558356f5 x_refsource_MISC
https://github.com/onnx/onnx/releases/tag/v1.22.0 x_refsource_MISC