Cyber Resilience

CVE-2026-34446

Path Traversal in Linuxfoundation Onnx ≤ 1.21.0

Published
01 April 2026
Modified
15 April 2026
Patch / advisory
CVSS Score v3.1 4.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS Score 0.0018 7th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-34446 is a medium-severity Path Traversal (CWE-22) vulnerability in Linuxfoundation Onnx. Its CVSS base score is 4.7 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as Machine Learning Libraries; in the Supply Chain and Deployment risk domain.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. Prior to version 1.21.0, there is an issue in onnx.load, the code checks for symlinks to prevent path traversal, but completely misses hardlinks because a hardlink looks…

more

exactly like a regular file on the filesystem. This issue has been patched in version 1.21.0.

CWE(s)

AI Security AnalysisAI

AI Category
Machine Learning Libraries
Risk Domain
Supply Chain and Deployment
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: machine learning, neural network, onnx

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
Why these techniques?

Hardlink-based path traversal in onnx.load directly enables unauthorized reads from the local filesystem outside intended directories.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-34447Same product: Linuxfoundation Onnx
CVE-2026-27489Same product: Linuxfoundation Onnx
CVE-2025-51480Same product: Linuxfoundation Onnx
CVE-2024-5187Same product: Linuxfoundation Onnx
CVE-2024-27318Same product: Linuxfoundation Onnx
CVE-2026-35167Same vendor: Linuxfoundation
CVE-2026-3840Same vendor: Linuxfoundation
CVE-2026-33211Same vendor: Linuxfoundation
CVE-2025-59352Same vendor: Linuxfoundation
CVE-2026-25152Same vendor: Linuxfoundation

Affected Assets

linuxfoundation
onnx
≤ 1.21.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-2 Flaw Remediation
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V5.3.2
  • V5.2.5

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces validation of file paths and link types during onnx.load to block path traversal via hardlinks (CWE-22/61).

prevent

Requires timely application of the vendor patch (v1.21.0) that adds hardlink detection to the existing symlink check.

prevent

Limits the filesystem privileges granted to the process performing onnx.load, reducing impact of any successful hardlink traversal.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent introduction of symlink-following flaws in file-handling code.

ID.RA-01 partial match
prevents

Vulnerability identification can discover existing symlink issues but does not prevent or remediate them in code.

PR.AA-05 partial match
prevents

Least-privilege access policies can limit damage from symlink attacks but do not address the coding flaw itself.

PR.PS-02 partial match
prevents

Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development catches path traversal via static/dynamic analysis.

prevents

Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.

prevents

Application security requirements include rules for safe file handling and canonicalization.

prevents

Secure architecture principles require least-privilege file access and directory isolation.

prevents

Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.

mitigates

Information access restriction limits which files an application may read or write.

References