CVE-2026-49114

Description

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.

References

https://www.cve.org/CVERecord?id=CVE-2026-49114

https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json

https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3

CVSS v4