{"id":"CVE-2026-4137","aliases":["BIT-mlflow-2026-4137","GHSA-f2m9-wcf4-cwwx","PYSEC-2026-2655"],"url":"https://o3.security/vulnerability/CVE-2026-4137","summary":"Incomplete Fix for CVE-2025-10279: Insecure Temporary Directory Permissions in mlflow/mlflow","details":"In mlflow/mlflow versions prior to 3.11.0, the `get_or_create_nfs_tmp_dir()` function in `mlflow/utils/file_utils.py` creates temporary directories with world-writable permissions (0o777), and the `_create_model_downloading_tmp_dir()` function in `mlflow/pyfunc/__init__.py` creates directories with group-writable permissions (0o770). These insecure permissions allow local attackers to tamper with model artifacts, such as cloudpickle-serialized Python objects, and achieve arbitrary code execution when the tampered artifacts are deserialized via `cloudpickle.load()`. This vulnerability is particularly critical in environments with shared NFS mounts, such as Databricks, where NFS is enabled by default. The issue is a continuation of the vulnerability class addressed in CVE-2025-10279, which was only partially fixed.","published":"2026-05-18T20:26:23.104Z","modified":"2026-08-12T03:51:14.665028235Z","cvss":{"score":7,"severity":"HIGH","vector":"CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00193,"percentile":0.09247,"asOf":"2026-08-14"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"mlflow","fixedVersion":"3.11.0"}],"fix":{"url":"https://github.com/mlflow/mlflow/commit/1dcbb0c2fbd1f446c328830e601ca13a28219b8a","label":"mlflow/mlflow@1dcbb0c"},"references":[{"type":"WEB","url":"https://huntr.com/bounties/648dc30b-76c7-4433-86b8-f43d926fd8d6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4137.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4137"},{"type":"FIX","url":"https://github.com/mlflow/mlflow/commit/1dcbb0c2fbd1f446c328830e601ca13a28219b8a"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:14.665028235Z"}}