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High VA-26-233-01 1 CVE

ONNX symlink-following and path-traversal arbitrary file write

Published Aug 21, 2026 · Updated Aug 21, 2026

Summary

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.

Vulnerabilities 1

  • High 7.1

    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_NOFOLLOW/O_EXCL', after a non-atomic 'os.path.isfile()' check. A local attacker with …

Revision history

  1. #1.0.0

    Initial publication