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 an
CVSS
7.1
High
EPSS
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KEV
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Exploit Today
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0-100
Published: Aug 21, 2026 · Last modified: Aug 21, 2026 · CWE-22 · CWE-59 · CWE-367
Not enough EPSS history yet.
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.