Vulnerability in Lfprojects Mlflow
CVE-2026-4137
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 · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (5.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: -0.000
Affected products
- Lfprojects Mlflow
- Mlflow Mlflow/mlflow — versions unspecified
Weakness classification (CWE)
References
- huntr.com/bounties/648dc30b-76c7-4433-86b8-f43d926fd8d6 (Exploit, Third Party Advisory)
- github.com/mlflow/mlflow/commit/1dcbb0c2fbd1f446c328830e601ca13a28219b8a (Patch)
Frequently asked questions
- What is CVE-2026-4137?
- CVE-2026-4137 is a high-severity vulnerability in Lfprojects Mlflow, classified under Creation of Temporary File With Insecure Permissions. CVSS score: 7.8/10. Published 2026-05-18.
- How severe is CVE-2026-4137?
- High severity. CVSS v3 base score is 7.8 out of 10.