CVE-2026-49114 — ONNX symlink-following and path-traversal arbitrary file write
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_NOF…
Published: 2026-08-21 · CVSS: 6.8 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7