PatchSiren cyber security CVE debrief

CVE-2026-27489 onnx CVE debrief

CVE-2026-27489 is a high-severity vulnerability in Open Neural Network Exchange (ONNX), a standard for machine learning interoperability. Prior to version 1.21.0, ONNX was susceptible to a path traversal vulnerability via symlink, allowing attackers to read arbitrary files outside the model or user-provided directory. This issue has been patched in version 1.21.0. The vulnerability has a CVSS score of 8.7 and is classified as HIGH severity. The CVE was published on April 1, 2026, and last modified on June 30, 2026.

Vendor: onnx
Product: Unknown
CVSS: HIGH 8.7
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-04-01
Original CVE updated: 2026-07-15
Advisory published: 2026-04-01
Advisory updated: 2026-07-15

Who should care

Organizations using Open Neural Network Exchange (ONNX) versions prior to 1.21.0 should prioritize patching this vulnerability to prevent potential file reads. Machine learning and AI practitioners, as well as security teams, should be aware of this vulnerability and take necessary actions to protect their systems.

Technical summary

The path traversal vulnerability in ONNX allows attackers to read arbitrary files outside the model or user-provided directory via symlink. This issue was patched in version 1.21.0. The vulnerability has a CVSS score of 8.7, indicating high severity. The attack vector is network-based, and the vulnerability can be exploited without user interaction. The CWE associated with this vulnerability is CWE-23 and CWE-61.

Defensive priority

Patching to version 1.21.0 or later is strongly recommended. Organizations should also review their ONNX deployments and ensure that they are not exposed to untrusted inputs.

Recommended defensive actions

Patch ONNX to version 1.21.0 or later
Review ONNX deployments for exposure to untrusted inputs
Monitor for suspicious activity related to ONNX usage
Implement additional security controls to prevent exploitation
Conduct a thorough risk assessment of ONNX usage in the organization

Evidence notes

The CVE record and NVD detail provide information on the vulnerability, its severity, and the patching information. The source item URL provides additional details on the vulnerability and its impact.

Sources and references

Verified primary and authoritative sources

CVE-2026-27489 CVE Program record
Publisher, destination, and source semantics verified

URL: https://www.cve.org/CVERecord?id=CVE-2026-27489

CVE Program - Official CVE Program record with source-provided CVE metadata.
CVE-2026-27489 NVD vulnerability detail
Publisher, destination, and source semantics verified

URL: https://nvd.nist.gov/vuln/detail/CVE-2026-27489

NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Mitigation or vendor reference
Unverified legacy reference

URL: https://github.com/onnx/onnx/commit/4755f8053928dce18a61db8fec71b69c74f786cb

[email protected] - Patch
Mitigation or vendor reference
Unverified legacy reference

URL: https://github.com/onnx/onnx/security/advisories/GHSA-3r9x-f23j-gc73

[email protected] - Exploit, Mitigation, Patch, Vendor Advisory
Source reference
Unverified legacy reference

URL: https://access.redhat.com/errata/RHSA-2026:24977

0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source reference
Unverified legacy reference

URL: https://access.redhat.com/security/cve/CVE-2026-27489

0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source reference
Unverified legacy reference

URL: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27489.json

0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.