CVE Intelligence
Medium

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

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.

Published Oct 26, 2026 · Updated Oct 26, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Onnx
Onnx
CVSS base
6.2
Medium · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Onnx Onnx).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Onnx Onnx version >= 1.4.0, < 1.22.0 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.2 CVSS 3.1 Medium 2.5 3.6 security-advisories@github.com via NIST National Vulnerability Database
6.2 CVSS 3.1 Medium — — GitHub_M via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-195

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Published → Awaiting Analysis
    Oct 26, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 26, 2026
  • CVSS changed · 6.2
    Oct 26, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 26, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 26, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Oct 26, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 26, 2026 – Oct 26, 2026

References

4 on the record

Elsewhere on this site

Onnx
every CVE for this vendor
CWE-195
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-115922 ONNX: Denial of service via unchecked expansion of packed sub-byte tensors in ONNX Python APIs 3h
  • CVE-2026-115919 ONNX: Out-of-Bounds Read in RNN/GRU/LSTM Shape Inference (Old Opsets, Missing Rank Check) 3h
  • CVE-2026-115920 ONNX: Out-of-bounds read in ConvTranspose shape inference via undersized weight rank 3h
  • CVE-2026-49114 ONNX symlink-following and path-traversal arbitrary file write Aug 21, 2026
  • CVE-2026-63632 ONNX: Heap-Buffer-Overflow READ in Gemm Version Converter Adapter via Undersized Input Shape Aug 18, 2026
  • CVE-2026-44512 ONNX: Null Pointer Dereference in Upsample Version Converter Adapter (Zero Inputs) Jul 8, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-115921 is "ONNX: Null Pointer Dereference in ScanInferenceFunction Due to Missing Required Attribute", rated Medium. It affects Onnx (Onnx); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.2 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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