Authorization Bypass in MLflow AJAX Endpoint

published 2026-04-07 7 mo ago modified 2026-09-10 1 mo ago also BIT-mlflow-2026-33866 , EUVD-2026-19609 , GHSA-46r5-x6jq-v8g6 , PYSEC-2026-94

cvss: 4.3; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits: 0; none known

MLflow is vulnerable to an authorization bypass affecting the AJAX endpoint used to download saved model artifacts. Due to missing access‑control validation, a user without permissions to a given experiment can directly query this endpoint and retrieve model artifacts they are not authorized to access.

This issue affects MLflow version through 3.10.1

Patch / fix

fixed in 2 links 2

pypi mlflow 3.11.0rc0
bitnami mlflow 3.11.1

github.com/mlflow/mlflow@005b959 commit
github.com/mlflow/mlflow#21708 pull request

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33866 updated 2026-07-05 cvss 6.5

MLflow: MLflow: Information disclosure via authorization bypass in AJAX endpoint

Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-th06-cpu-torch210-py312-rhel9, rhoai/odh-th06-rocm64-torch291-py312-rhel9, rhoai/odh-th06-cuda130-torch210-py312-rhel9, rhoai/odh-training-cuda128-torch29-py312-rhel9, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9, +11 more
affected: workaround, no fix available “Fix deferred”
Red Hat OpenShift AI (RHOAI) rhoai/odh-pipeline-runtime-tensorflow-rocm-py312-rhel9, rhoai/odh-workbench-jupyter-tensorflow-rocm-py312-rhel9
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 6 mo ago (2026-04-14)

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

afine.com https://afine.com/blogs/attacking-mlflow-how-ml-artifacts-become-attack-vectors referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
GitHub	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CNA	4.0	5.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
OSV	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
pypi	mlflow	<3.11.0rc0	3.11.0rc0
bitnami	mlflow	<3.11.1	3.11.1

Affected products

Mlflow Mlflow

Classification

Weakness

CWE-862 Missing Authorization

References

github.com /mlflow/mlflow/pull/21708
patch, web, issue-tracking
github.com /mlflow/mlflow/commit/005b959cacda05d1423356cfcbd9ebeda8ff96a7
web
afine.com /blogs/attacking-mlflow-how-ml-artifacts-become-attack-vectors
exploit, technical-description, web, third-party-advisory, advisory, evidence
cert.pl /en/posts/2026/04/CVE-2026-33865/
third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2026-33866
advisory, web
cert.pl /en/posts/2026/04/CVE-2026-33865
web
github.com /mlflow/mlflow
package
github.com /pypa/advisory-database/tree/main/vulns/mlflow/PYSEC-2026-94.yaml
web
github.com /advisories/GHSA-46r5-x6jq-v8g6
advisory

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary