CVE-2026-49114
Medium
Elevated severity or exploit probability.
CVSS base
7.1
HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
EPSS — probability of exploitation (30 days)
0.2%
5.5th percentile
CISA KEV
Not listed
Weakness / dates
CWE-22
Published 2026-08-21 · modified 2026-09-16
CVSS breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
| Attack Vector | L | Local |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | R | Required |
| Scope | U | Unchanged |
| Confidentiality | N | None |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2026-08-21 — Published (NVD)
- 2026-09-16 — Last modified (NVD)
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.