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 4.0
- 6.8
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.1
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 5% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-22, CWE-59, CWE-367
- Published
- Modified
- Record from
- the NVD, synced
Affected
- linuxfoundation:onnx
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-q56x-g2fj-4rj6 | PyPI | onnx | <1.21.0 | 1.21.0 |
| PYSEC-2026-3876 | PyPI | onnx | <1.21.0 | 1.21.0 |