CVE-2026-49114

In ONNX before 1.21.0, the 'save_external_data' function builds the external-data file path from the model's external_data location field and opens it for writing without 'O_NOFOLLOW/O_EXCL', after a non-atomic 'os.path.isfile()' check. A local attacker with write access to the directory where a victim serializes external data can deterministically pre-plant a symlink that is being followed, causing the victim's write to append to any file the victim can write, e.g. ~/.ssh/authorized_keys, cron files, or application configs. Fixed in 1.21.0.

CVSS v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6	Exploit Vendor Advisory
https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json	VDB Entry
https://www.cve.org/CVERecord?id=CVE-2026-49114	Third Party Advisory VDB Entry

Configurations

Configuration 1 (hide)

cpe:2.3:a:linuxfoundation:onnx:*:*:*:*:*:*:*:*

History

16 Sep 2026, 13:44

Type	Values Removed	Values Added
CPE		cpe:2.3:a:linuxfoundation:onnx::::::::
First Time		Linuxfoundation onnx Linuxfoundation
References	~~() https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6 -~~	() https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6 - Exploit, Vendor Advisory
References	~~() https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json -~~	() https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json - VDB Entry
References	~~() https://www.cve.org/CVERecord?id=CVE-2026-49114 -~~	() https://www.cve.org/CVERecord?id=CVE-2026-49114 - Third Party Advisory, VDB Entry

Information

Published : 2026-08-21 16:17

Updated : 2026-09-16 13:55

NVD link : CVE-2026-49114

Mitre link : CVE-2026-49114

CVE.ORG link : CVE-2026-49114

JSON object : View

Products Affected

linuxfoundation

onnx

CWE

CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CWE-59

Improper Link Resolution Before File Access ('Link Following')

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition

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