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Vulnerabilities

Vulnerability · CVE-2026-115921

ONNX: Null Pointer Dereference in ScanInferenceFunction Due to Missing Required Attribute

Published Oct 26, 2026 · catalog updated Oct 31, 2026 · Red Hat Red Hat Enterprise Linux

Last checked Nov 5, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-115921. EPSS is 0.13%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.13%
Remediation
Version ranges on file
Affected products
pip onnx · pypi onnx

## Summary ONNX shape inference did not safely validate the required Scan attribute. Two malformed values could terminate or disrupt the process: 1. If the attribute was missing, returned null and was dereferenced. 2. If the attribute was negative, conversion to produced a very large value that reached a vector allocation and raised . The negative-value variant passed before reaching shape inference. ## Technical details The vulnerable Scan inference implementations used the following pattern: This code neither checked the returned pointer nor rejected a negative signed value before converting it to an unsigned size. The pattern was present in the current Scan inference function and the older opset 8 and 9 paths. The fix uses the required-attribute helper and checked narrowing: ## Impact An application that performs shape inference on an untrusted model can be terminated or forced into an exceptional allocation path, causing denial of service. No confidentiality or integrity impact was demonstrated. ## Affected versions - Affected: ONNX 1.4.0 through 1.21.0 - Patched: ONNX 1.22.0 ONNX 1.4.0 is the first release containing the vulnerable Scan shape-inference implementation. ## Remediation Upgrade to ONNX 1.22.0 or later. - Fix: [onnx/onnx#7916](https://github.com/onnx/onnx/pull/7916) - Commit: [ ](https://github.com/onnx/onnx/commit/dd6bc92ea39fd2274fd671f0734b0b8b558356f5) Both reported models were re-tested against the published ONNX 1.23.2 wheel and correctly raise . ## Severity The vulnerable ONNX component processes the malicious model through a local library API or file boundary and is not itself bound to a network stack. Applications that expose ONNX model processing over a network should calculate an Environmental score with Modified Attack Vector set to Network. The two triggers remain in one advisory because they affect the same required attribute, share the same unsafe conversion path and remediation, and were fixed in the same release.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • pip onnx>= 1.4.0, <= 1.21.0
  • pypi onnxversion unspecified

How to fix CVE-2026-115921

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-115921. EPSS is 0.13%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Which versions are affected?

Compare what you have installed with >= 1.4.0, <= 1.21.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-195; CWE-476: NULL Pointer Dereference. EPSS 0.13%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 26, 2026 · Red Hat Security Data

    Detected

    onnx: onnx: Denial of Service via improper attribute validation in Scan shape inference

  2. Oct 28, 2026 · GitHub Advisory Database

    Updated

    ## Summary ONNX shape inference did not safely validate the required Scan attribute. Two malformed values could terminate or disrupt the process: 1. If the attribute was missing, returned null and was dereferenced. 2. If the attribute was negative, conversion to produced a very large value that reached a vector allocation and raised . The negative-value variant passed before reaching shape inferen

  3. Oct 31, 2026 · NIST NVD

    Updated

    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 o

Sources

  • CVE.orgVulnerability recordCVE-2026-115921

    Official CVE identifier

    cve.org
  • GitHub Advisory DatabasePackage advisoryGHSA-m4pr-6v3c-6fgr

    ONNX: Null Pointer Dereference in ScanInferenceFunction Due to Missing Required Attribute

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-115921

    ONNX shape inference did not safely validate the required Scan num_scan_inputs attribute. Two malformed values could terminate or disrupt the process: If the attribute was missing, ctx.getAttribute("num_scan_inputs") returned null and was dereferenced. If the attribute was negative, conversion to size_t produced a very large value that reached a vector allocation and raised std::length_error. The

    advisories.gitlab.com
  • NIST NVDVulnerability recordCVE-2026-115921

    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 a

    nvd.nist.gov
  • Red Hat Security DataVendor advisoryCVE-2026-115921

    onnx: onnx: Denial of Service via improper attribute validation in Scan shape inference

    access.redhat.com

References

Freshness

Last verified in this catalog Nov 5, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • NIST NVDOct 31, 2026
  • GitHub Advisory DatabaseOct 30, 2026
  • GitLab Advisory DatabaseOct 29, 2026
  • CVE.orgOct 27, 2026
  • Red Hat Security DataOct 27, 2026